[Zennnnn]

Hey all,
I've been trying to find an m340i in a spec I want and evently came across a dealer selling an m340i xdrive with the following:
Premium Excellence Package
64k km
CTS intake
CTS Catless downpipe
CTS Charge pipe
MHD stage 2
xHP
Should I run away from this seeing as how heavily modified it is? What has your experience been with buying used modified cars?

[jg4c]

Originally Posted by Zennnnn

Hey all,
I've been trying to find an m340i in a spec I want and evently came across a dealer selling an m340i xdrive with the following:
Premium Excellence Package
64k km
CTS intake
CTS Catless downpipe
CTS Charge pipe
MHD stage 2
xHP
Should I run away from this seeing as how heavily modified it is? What has your experience been with buying used modified cars?

Walk away, and quickly.

[Zennnnn]

Even if the multi point inspection checks out? There are plenty of service records with preventative maintenance intervals and the title is clean. This is honestly the only reason I'm giving it a second glance. No claims on file, car looks immaculate.

[jg4c]

Personally, I’d consider it, if only my independent
BMW shop mechanic gave it an inspection
and the thumbs up.

You don’t mention the year, and mileage looks high.
Modified cars are usually driven pretty hard and
in some cases are beat on badly.

[Zennnnn]

Forgot to mention that, my bad. It's a 2020 with 64k km or about 40k miles. The Carfax shows then places he's serviced the car at does performance modifications and ech tuning so odds are he didn't just install the parts in his backyard (although the only way to know for sure would be to get the dealer to contact him and consent to talk to me about the history of the car and why he's selling it). I'll have to do some more digging

[cyam]

Originally Posted by Zennnnn

Hey all,
I've been trying to find an m340i in a spec I want and evently came across a dealer selling an m340i xdrive with the following:
Premium Excellence Package
64k km
CTS intake
CTS Catless downpipe
CTS Charge pipe
MHD stage 2
xHP
Should I run away from this seeing as how heavily modified it is? What has your experience been with buying used modified cars?

Its not "heavily modified" but it is modified. Its just an MHD tune on pump gas - that's not heavily modified. Otherwise it just has a downpipe, which on its own, if anything, will increase longevity not decrease it. The intake/charge pipe mean nothing - they do nothing except change the sound. XHP could reduce the longevity of the gearbox esp if they applied certain settings for really hard launches - those can be very taxing on the gearbox, but if they were not selected and just using a Stage 2 XHP tune, then it'd be fine.

The only reason I wouldn't consider this is not due to the mods per se, but because the driver/previous owner probably drove it hard. That's where the real issue would be for me.

When I buy a used car I always closely inspect the tires and brakes to see how they are wearing as they will give me a good indication to how the previous owner drove it. I always want to buy a car from someone who babied it around and that's never someone who mods it.

[peelerec]

If you’re seriously considering it, have a well known/reputable Indy shop perform a PPI. Also, is there a way to find out if previous owner activated launch control? I imagine it is somehow recorded on DME.

[Dan B]

Any engine or driveline issues you risk paying out of pocket.

If that is any concern do not buy it.

[PK2348]

Should be priced at a very deep discount, and then maybe

[zazzau]

Lone voice here: folks concerned about the car being driven hard - this is something you will never know regardless of whether you’re buying a mod’ed car or not. I don’t think that a tune is always an indication that the car has been beaten. While a closer look at the tire/brakes might be helpful, that’s assuming those weren’t recently replaced prior to going on the market.

In any case, these modern machines are built with greater reliability and the B58, so far, has proven to be reliable. As others have mentioned, get the car thoroughly inspected by a reliable hand.

Is there wiggle room to negotiate on pricing?

[Dan B]

Originally Posted by zazzau

Lone voice here: folks concerned about the car being driven hard - this is something you will never know regardless of whether you’re buying a mod’ed car or not. I don’t think that a tune is always an indication that the car has been beaten. While a closer look at the tire/brakes might be helpful, that’s assuming those weren’t recently replaced prior to going on the market.

In any case, these modern machines are built with greater reliability and the B58, so far, has proven to be reliable. As others have mentioned, get the car thoroughly inspected by a reliable hand.

Is there wiggle room to negotiate on pricing?

I think we can assume that someone that tunes their car does so for performance. That would reasonably infer they drive the car hard.

[GD1981]

Certainly not ideal to get a modified car; though at 730 whp on my M340i, I can tell you that the B58 can handle loads of power. It becomes more about the maintenance - and whether the original owner did the maintenance at a greater frequency.

I’m pretty anal with my car, both in how it appears and the maintenance aspect of it.. I change my oil every 3-4k miles and spark plugs, every 12k miles. Car hasn’t skipped a beat, and the last oil analysis I did, everything checked out a-ok. Again, it is really all about the maintenance and how the previous owner treated the car.

[aleph-one]

Originally Posted by Dan B

I think we can assume that someone that tunes their car does so for performance. That would reasonably infer they drive the car hard.

You cannot, correlation does not imply causation. There are absolutely plenty of stock cars driven harder than modified examples. You could just as easily assume that those who modify their cars are enthusiasts who take very good care of them. My car has basically the same setup and I still baby it, only enjoying the extra power on the occasional pull.

Originally Posted by GD1981

Certainly not ideal to get a modified car; though at 730 whp on my M340i, I can tell you that the B58 can handle loads of power. It becomes more about the maintenance - and whether the original owner did the maintenance at a greater frequency.

I’m pretty anal with my car, both in how it appears and the maintenance aspect of it.. I change my oil every 3-4k miles and spark plugs, every 12k miles. Car hasn’t skipped a beat, and the last oil analysis I did, everything checked out a-ok. Again, it is really all about the maintenance and how the previous owner treated the car.

This. The bottom line is how well it was maintained. I would sooner buy a bolt-on car from someone who I knew maintained it this well than some random stock example with the same mileage from carmax.

[RTPenland]

Originally Posted by aleph-one

You cannot, correlation does not imply causation. There are absolutely plenty of stock cars driven harder than modified examples. You could just as easily assume that those who modify their cars are enthusiasts who take very good care of them. My car has basically the same setup and I still baby it, only enjoying the extra power on the occasional pull.



This. The bottom line is how well it was maintained. I would sooner buy a bolt-on car from someone who I knew maintained it this well than some random stock example with the same mileage from carmax.

was just going to jump in here and say all this but you already did - well said thank you

[cyam]

Originally Posted by GD1981

Certainly not ideal to get a modified car; though at 730 whp on my M340i, I can tell you that the B58 can handle loads of power. It becomes more about the maintenance - and whether the original owner did the maintenance at a greater frequency.

I’m pretty anal with my car, both in how it appears and the maintenance aspect of it.. I change my oil every 3-4k miles and spark plugs, every 12k miles. Car hasn’t skipped a beat, and the last oil analysis I did, everything checked out a-ok. Again, it is really all about the maintenance and how the previous owner treated the car.

GEARBOX! Thats where the issues are on tuned engines, not the engine. If you get on the gas before the gearbox fluid is up to op temp, you cause premature wear - especially in a mod'd car. The tune, if it isn't sending the correct info to the TCU you can decimate the gearbox. Then there is GEARBOX maintenance - changing the fluid min every 50k miles etc etc.

You can't know any of these things REGARDLESS of how well you maintain the engine.

Bottom line the more you push a car the quicker it wears out. People that do engine mods push their car harder - as a general rule. It don't matter how well you maintain it - it is certainly better than a tuned car not maintained, but that doesn't cover up the mods.

Buying a mod'd car is far riskier than buying stock. Simple. You buy a mod'd car you accept an elevated risk.

[Dan B]

Originally Posted by aleph-one

You cannot, correlation does not imply causation. There are absolutely plenty of stock cars driven harder than modified examples. You could just as easily assume that those who modify their cars are enthusiasts who take very good care of them. My car has basically the same setup and I still baby it, only enjoying the extra power on the occasional pull.

A couple of things here.

You are ignoring the statement I was replying to, so your response only addresses my statement taken out of context.

zazzau makes a valid statement that modified cars means does not mean "always" driven hard.

Originally Posted by zazzau

. I don’t think that a tune is always an indication that the car has been beaten.

My statement was not disputing this. I was simply stating that if they modify the car they probably drive it hard. I did not say "..drive it hard all of the time". Using more power than stock causes more wear.

You also say "There are absolutely plenty of stock cars driven harder than modified examples". That is irrelevant. We are not debating if stock or modified cars are driven harder.

Your statement "correlation does not imply causation" is more aptly applied if we were to say "Modified car owners drink more soda". The argument is, you modify the car so it uses more gas. This means you go to the gas station more and while you are there, you buy a soda. So modifying a car = drinking more soda. That is causation.

You can correlate modifying a car with driving it harder because you tune a car for more power. It is a reasonable assumption that they are not modifying it, increasing the power, and then not driving it harder.

This is the internet so I expect someone will say they tuned the car to be more efficient or for some other reason. Please don't. You are an anomaly. BMW has a massive data set that allows them to tune their vehicles to be as efficient as possible for the majority of use case scenarios.

The fact that you only use the extra power occasionally is an infinitesimally small data point. Every single owner I know that has modified their car, uses the extra power. Often. And I am an adult so the subset I am referencing are "adult" driven cars. So using well established data that shows as you age, you drive more carefully, we can reasonably infer the subset I am referencing babys their cars more than the younger subset.

Yes, maintenance is the key to any cars longevity. Stock or modified. But unless you are pulling parts and doing things like ultrasound testing, or replacing parts more frequently, there is a higher chance of failure on a modified than stock vehicle.

Finally, the OP was asking if they should be concerned about the car being modified. It is more than reasonable to say yes, use extra caution with modified cars.

[GD1981]

Originally Posted by cyam

GEARBOX! Thats where the issues are on tuned engines, not the engine. If you get on the gas before the gearbox fluid is up to op temp, you cause premature wear - especially in a mod'd car. The tune, if it isn't sending the correct info to the TCU you can decimate the gearbox. Then there is GEARBOX maintenance - changing the fluid min every 50k miles etc etc.

You can't know any of these things REGARDLESS of how well you maintain the engine.

Bottom line the more you push a car the quicker it wears out. People that do engine mods push their car harder - as a general rule. It don't matter how well you maintain it - it is certainly better than a tuned car not maintained, but that doesn't cover up the mods.

Buying a mod'd car is far riskier than buying stock. Simple. You buy a mod'd car you accept an elevated risk.

It is riskier for sure.

Having said that, I had a 2016 340i that was tuned to about 480 whp on E50. Owned it for the first 52k miles, sold it to my cousin, and got an M340i. My cousin still has the car today, with more mods, and the car has 115k miles on it with no issues outside normal wear and tear. Not saying the car will continue to serve him well as he keeps it longer, but with prudent maintenance, the odds are improved.

To the OP, if you have zero intentions of modding a 340i and are concerned with long term reliability, look elsewhere.

[GD1981]

Originally Posted by cyam

GEARBOX! Thats where the issues are on tuned engines, not the engine. If you get on the gas before the gearbox fluid is up to op temp, you cause premature wear - especially in a mod'd car. The tune, if it isn't sending the correct info to the TCU you can decimate the gearbox. Then there is GEARBOX maintenance - changing the fluid min every 50k miles etc etc.

You can't know any of these things REGARDLESS of how well you maintain the engine.

Bottom line the more you push a car the quicker it wears out. People that do engine mods push their car harder - as a general rule. It don't matter how well you maintain it - it is certainly better than a tuned car not maintained, but that doesn't cover up the mods.

Buying a mod'd car is far riskier than buying stock. Simple. You buy a mod'd car you accept an elevated risk.

I have a built trans.

[aleph-one]

Originally Posted by Dan B

A couple of things here.

No, to all of this.

Your hypothesis is very clear. It could be read on the back of a newspaper and still be just as invalid. I should point out that I don't even disagree with you on principle, the reason I jumped in here to reply to you is because I'm a statistician and your comment disturbed me.

You make two assumptions: first, that people who tune their cars do so for performance; second, you can infer from knowing that a car is tuned that a person drives their car hard. The second assumption builds on the first, and is the more offensive one because you can't infer anything. The fact that these are assumptions is absolute, the best you can do is prove that they are most likely true and that the probability of them being untrue is so slim you would only observe it in an insignificant portion of a population (usually less than 5% or two standard deviations from the mean of a normal distribution). You haven't done this because you don't have data and didn't do any math. It's a hypothesis without any proof and there are many cases in which it is false.

In response to a couple of your statements:

Originally Posted by Dan B

We are not debating if stock or modified cars are driven harder.

I agree, but my point is still relevant. A stock car that is regularly driven hard and not maintained well (I would wager this applies to a LOT of BMW drivers, especially young ones) would have more wear than a modified car that was well taken care of. So, you cannot infer with no other information that a tuned car will have more wear. It's impossible. The only way to know for sure would be to test them, which we can do! I have a binder full of blackstone reports on engine oil AND transmission fluid from several tuned cars that are well within spec. You could sample a stock car owned by a teenager who rags on it and see much worse wear. Again, this is to show that you cannot infer anything based on your assumptions alone.

Originally Posted by Dan B

"correlation does not imply causation"

In any good first year statistics course, students will be told something like "Ice cream purchases and shark attacks both increase in the summer, therefore eating ice cream must make you more likely to be attacked by a shark", as a way to describe the correlation vs. causation trap. This example (or something similar) is probably what you were thinking of when you made your soda analogy. The real message of this lesson is that there is a commonality between these two outcomes and that is people who go to the beach, who are statistically more likely to experience either. Being at the beach in this case is a 'covariate', an important piece of information about a population that makes ice cream and sharks more likely, and explains why those outcomes are not directly related.

The correlation in your statement is "tuned cars" and "hard driving" (this must be true seeing as you believe you can infer one from the other). Your assumption (called the alternative hypothesis) is that people who tune their cars drive them hard. However, there is any number of covariates that would skew this assumption, age probably being the biggest one as you mention. E.g. you could hypothesize that a young driver is more likely to tune their cars AND drive them hard, or just one or the other. The same could be hypothesized about a driver with several speeding tickets, or a driver with an abnormally high insurance premium. As you say, an old driver is likely to not drive their car hard, ask yourself: is that still true if the car happens to be tuned? Note my use of "hypothesize" instead of "assume", because without an actual analysis we can only make estimates and cannot assume them to be true. It doesn't matter whether your assumption is "reasonable", it is likely that there are several factors that influence the outcome. We could solve for this with whats called a multiple regression analysis, which produces mathematical weights to the influence of covariates on outcomes.

Again, none of this is to say that I fundamentally disagree with your assumption or that it wouldn't happen to be correct in many cases. However, in science we have to be VERY careful with the assumptions we make, how we phrase them, and whether we hold them to be true. I'm not trying to be pedantic here, it's just good knowledge to have and it keeps us objective.

To the OP: Once again, I would buy a bolt-on daily driver from someone with good maintenance records, a ppi, and some blackstone reports ten times out of ten before I bought one off a dealer or an individual that has little to no history recorded. It is completely possible (and dare I say, likely) that the babied tuner would have less wear and more longevity than the stock mystery car. I can prove this with my own car, which has been tuned for 20k miles and still gets gleaming reports on every fluid you could possibly send out for testing. Now, if neither car has history, avoid the tuner like the plague (in this particular case, Dan B's assumption could very well be correct). I would also avoid it if it is being sold be a teenager. But, if the seller has decent service history and you can get a PPI on it and maybe even a blackstone analysis if they are generous, then I would personally go for it. BTW, OTS tunes like MHD/BM3 and XHP for the trans are made for mass market, which means they are specifically designed to increase limits without decreasing reliability/longevity to any significant degree that wouldn't be offset by regular maintenance. If it was custom tuned and used as a dragster or a drift missile, skip it. Just do your due diligence and you will make the right decision.

[GD1981]

Originally Posted by aleph-one

No, to all of this.

Your hypothesis is very clear. It could be read on the back of a newspaper and still be just as invalid. I should point out that I don't even disagree with you on principle, the reason I jumped in here to reply to you is because I'm a statistician and your comment disturbed me.

You make two assumptions: first, that people who tune their cars do so for performance; second, you can infer from knowing that a car is tuned that a person drives their car hard. The second assumption builds on the first, and is the more offensive one because you can't infer anything. The fact that these are assumptions is absolute, the best you can do is prove that they are most likely true and that the probability of them being untrue is so slim you would only observe it in an insignificant portion of a population (usually less than 5% or two standard deviations from the mean of a normal distribution). You haven't done this because you don't have data and didn't do any math. It's a hypothesis without any proof and there are many cases in which it is false.

In response to a couple of your statements:



I agree, but my point is still relevant. A stock car that is regularly driven hard and not maintained well (I would wager this applies to a LOT of BMW drivers, especially young ones) would have more wear than a modified car that was well taken care of. So, you cannot infer with no other information that a tuned car will have more wear. It's impossible. The only way to know for sure would be to test them, which we can do! I have a binder full of blackstone reports on engine oil AND transmission fluid from several tuned cars that are well within spec. You could sample a stock car owned by a teenager who rags on it and see much worse wear. Again, this is to show that you cannot infer anything based on your assumptions alone.



In any good first year statistics course, students will be told something like "Ice cream purchases and shark attacks both increase in the summer, therefore eating ice cream must make you more likely to be attacked by a shark", as a way to describe the correlation vs. causation trap. This example (or something similar) is probably what you were thinking of when you made your soda analogy. The real message of this lesson is that there is a commonality between these two outcomes and that is people who go to the beach, who are statistically more likely to experience either. Being at the beach in this case is a 'covariate', an important piece of information about a population that makes ice cream and sharks more likely, and explains why those outcomes are not directly related.

The correlation in your statement is "tuned cars" and "hard driving" (this must be true seeing as you believe you can infer one from the other). Your assumption (called the alternative hypothesis) is that people who tune their cars drive them hard. However, there is any number of covariates that would skew this assumption, age probably being the biggest one as you mention. E.g. you could hypothesize that a young driver is more likely to tune their cars AND drive them hard, or just one or the other. The same could be hypothesized about a driver with several speeding tickets, or a driver with an abnormally high insurance premium. As you say, an old driver is likely to not drive their car hard, ask yourself: is that still true if the car happens to be tuned? Note my use of "hypothesize" instead of "assume", because without an actual analysis we can only make estimates and cannot assume them to be true. It doesn't matter whether your assumption is "reasonable", it is likely that there are several factors that influence the outcome. We could solve for this with whats called a multiple regression analysis, which produces mathematical weights to the influence of covariates on outcomes.

Again, none of this is to say that I fundamentally disagree with your assumption or that it wouldn't happen to be correct in many cases. However, in science we have to be VERY careful with the assumptions we make, how we phrase them, and whether we hold them to be true. I'm not trying to be pedantic here, it's just good knowledge to have and it keeps us objective.

To the OP: Once again, I would buy a bolt-on daily driver from someone with good maintenance records, a ppi, and some blackstone reports ten times out of ten before I bought one off a dealer or an individual that has little to no history recorded. It is completely possible (and dare I say, likely) that the babied tuner would have less wear and more longevity than the stock mystery car. I can prove this with my own car, which has been tuned for 20k miles and still gets gleaming reports on every fluid you could possibly send out for testing. Now, if neither car has history, avoid the tuner like the plague (in this particular case, Dan B's assumption could very well be correct). I would also avoid it if it is being sold be a teenager. But, if the seller has decent service history and you can get a PPI on it and maybe even a blackstone analysis if they are generous, then I would personally go for it. BTW, OTS tunes like MHD/BM3 and XHP for the trans are made for mass market, which means they are specifically designed to increase limits without decreasing reliability/longevity to any significant degree that wouldn't be offset by regular maintenance. If it was custom tuned and used as a dragster or a drift missile, skip it. Just do your due diligence and you will make the right decision.

Very well said. Just cause I have a heavily modded M340 doesnt mean I beat the crap out of it - in fact the majority of the time Im just crusing around. I just like the fact that I can access 700+ hp whenever I want to.

Also, since my car is RWD, I refuse to do hard launches on the car - most of my pulls are done on the highway, like 60-130 pulls.

I’ll disagree with you on one point, I’d rather have a custom tune over an ots. Custom tunes, when done correctly, are always better than ots. OTS doesn’t factor quality of fuel nor your elevation which has impact on your logs…especially true for 91/93 ots vs 91/93 custom tune…think timing corrections.

[zazzau]

Originally Posted by Dan B

My statement was not disputing this. I was simply stating that if they modify the car they probably drive it hard. I did not say "..drive it hard all of the time". Using more power than stock causes more wear.

You also say "There are absolutely plenty of stock cars driven harder than modified examples". That is irrelevant. We are not debating if stock or modified cars are driven harder.

Your statement "correlation does not imply causation" is more aptly applied if we were to say "Modified car owners drink more soda". The argument is, you modify the car so it uses more gas. This means you go to the gas station more and while you are there, you buy a soda. So modifying a car = drinking more soda. That is causation.

You can correlate modifying a car with driving it harder because you tune a car for more power. It is a reasonable assumption that they are not modifying it, increasing the power, and then not driving it harder.

This is the internet so I expect someone will say they tuned the car to be more efficient or for some other reason. Please don't. You are an anomaly. BMW has a massive data set that allows them to tune their vehicles to be as efficient as possible for the majority of use case scenarios.

The fact that you only use the extra power occasionally is an infinitesimally small data point. Every single owner I know that has modified their car, uses the extra power. Often. And I am an adult so the subset I am referencing are "adult" driven cars. So using well established data that shows as you age, you drive more carefully, we can reasonably [...]

You’re making this more complicated than it needs to be.

[aleph-one]

Originally Posted by GD1981

I’ll disagree with you on one point, I’d rather have a custom tune over an ots. Custom tunes, when done correctly, are always better than ots. OTS doesn’t factor quality of fuel nor your elevation which has impact on your logs…especially true for 91/93 ots vs 91/93 custom tune…think timing corrections.

This is reasonable. I live at altitude and should probably get a custom map made for it.

It's all about use case.

Originally Posted by zazzau

You’re making this more complicated than it needs to be.

I'd bet you meant to respond to me instead