Here is my experience with the F80 —> G20 transition (a lot of similarities with the OP):
G20 review
Looks
Outside:
I find the car looking great, nicely proportional and the Mineral Grey is excellent (and very underrated) on the G20. The front is a nice evolution from the F30. Initially, I was not sure about the rear, however, it looks modern and is nicely integrated. Overall, safe design, nice flow and proportions. Looks beautiful from the side view.
Inside
The inside again is a nice evolution of the previous design. Simple but driver oriented and functional. Basic spec (No premium or exec) of the features is more than enough. The technology is nicely integrated, I don’t see any glitches or issues and I like some improvements over the f30/80, for example auto folding mirrors option, sun roof cover (not a tech), more ADAS integrated, etc. Both, my F30 and F80 were pretty much loaded.
The base LED lights are good. I was concerned reading that they are weak, however, I don’t find them any different from my F80 icons.
The car is definitely an upgrade comfort-wise from the f30 MSport or F80. The seats are more comfortable, the noise is very isolated, no rattles (so far, 6 weeks into it), the cabin room increase is noticeable. I’ve had black leatherette in my e90, black leather in my e92, black leather in my 120d, coral red in f30, sakir orange in my f80 and now black leather in my g20 and feels like this leather is softest and of highest quality.
The noise isolation is...too much? Big difference when driving with open windows and closed. I’d like a little more noise but maybe I am just missing my f80...and still not pushing it over 4k (currently close to 1k miles).
Another step forward is how doors and trunk close. Much more luxurious feel and sound.
The B58 engine is great. Powerful, smooth, great sound. Very nicely mapped in stock form (comfort or sport). The 8AT is my first automatic car in 30+ years of driving. Well, second to be precise but the first one got me bored pretty quickly and lasted only 6-7 months. Now, I am close to 50, so, I think I am ready for it to do most of the work. The f80 6MT was excellent, I do miss it...just a little bit...
The B58 + 8ZF mate nicely, in every mode pretty much, comfort, sport, sport+. Well, Sport+ not sure yet. Drove it a few times but short because it holds the lower gear and begs to be pushed.
The weight gain is noticeable (as is the size gain), however, it also makes the chassis very stable. Looks like the engine and transmission are not bothered by a few extra pounds and move the car very quickly. The car does feel very fast although I’ve been keeping it under 4,000 rpm. But, I’ve done a few aggressive turns and this platform is definitely a huge step up over the f30 (not f80 though
).
Extremely well balanced.
I do find the standard suspension setup more than perfect. I’ve had adaptive suspension in my f80 and never used anything other than sport (a few times sport+). I don’t think I will be missing adaptive control...
The brakes are good. Initially feel grabby even coming off the f80. Feel adequate for the car.
Other
I’ve noticed that sensors are less sensitive - trunk opening with your foot under - most of the time nothing happens. Comfort unlock and lock is way less sensitive than with the F-series. I’ve had quite the opposite issues with my F80 trunk “opening by itself”, then I realized it would always happen when I walk by the trunk and trigger the sensor...
I am sure it will be more and more fun once I pass 1,200 miles mark however, this car is much closer to the F30 than the F80. And that is a good thing. Except for those that get confused by that badge on the trunk...