[Daily2023M340X]

Im looking at the MST Catted DP vs the AA Dp for my 2023 M340xDrive. Is there any real performance differences or quality differences? The MST has a 6" diameter, where as the AA has a 4.5” diameter that tapers to a 3.5”. Both are 400 CEL.

I have actually ordered the MST but there is a 3-4 week wait. If there is no real difference in terms of performance I dont see why I would wait if I could find an AA DP, but am having difficulty finding any info comparing the two.

Currently I am on a stock intake (waiting for MST With Turbo Inlet), car came stock with the M Performance Exhaust, and I am also running JB4 (until someone figures out how to unlock DME).

Any help is welcome!

[whofelt]

I don’t see how that would make any distance if at the end of the day it tapers down to 3.5 . Sounds more like a marketing thing is anything

[1QuikWS6]

IDK about the quality/fitment of the MST, but I can attest for the AA DP as I have had one installed on my 435 for yrs without CEL & no issues with emissions insp. here in PA, couple months on the M440 with both having perfect fitment.

6" cat element vs 4.5" with AA does sound like a marketing ploy - piping systems will only flow as much as the SMALLEST dia. pipe in the system. So, you would need to measure all the sections in both to compare apples to apples. If the rest of the piping of the MST is the same as AA then flow should be equal - obviously the dia. of the end that mates to your exhaust midpipe is the same on both = would be the restriction point for flow on each

While they both state No CEL Guarantee, the AA uses a GESi UHO-Series Catalytic Element that is EPA (but not CARB) registered and compliant in 49 states and fully OBD2 compliant, while the MST makes no mention of this. The AA DOES have an EPA# laser etched on the housing

Pricing of each is about the same based on AA sale thru Mike @ XPH (where I purchased both AA pipes) & I'm fairly certain the AA thru Mike is available immediately as he drop ships directly from AA

Knowing what I know about AA I would not wait for the MST, & go with AA every time

[totalone]

Have AA, Running for past 6 months. no cel, sounds nice.

[JunesM340IX]

This is nice to hear no cel ,is what's selling me since your post of 4/27/23 still no cell? and someone mentioned that their car passed PA emissions. the good thing about inspection in Delaware is that if the car is only 7 years old or newer no emissions test required.

[GA/\/\/\/\A_CT]

I’ve had an AA DP on an F30 for 2 years and a different AA DP on my g20 m340i for a year. Never a check engine light. Both cars passed emissions in CT.

Great fitment, sound, good bump in performance.