BMW sells a highly 'detuned' car - if you're buying a 3 series and you think it is the top cream of the market for handling and whatnot - think again.
What 'we' do (people that modify their cars) is personalization. You're right you don't 'have' to like it, but don't make untrue statements like they are the law.
1. Concrete aprons - Still not a problem in my 'dropped' car.
2. BMW's legendary handling ISN'T what's in these street cars (3 series stock). It's their racecars that made that 'legendary' title stick. Out of the box, a 3 series handles ok, and *is* a well balanced vehicle. If you think it's 'legendary' (hahahaha!) - go drive more car selections to expand your knowledge-base a bit..
3. Yes (and No!). However in the 'modding society' a nicely modded car will disappear quicker than a stock one. Seen it happen time and again in the local GA forum on B.f.C. Guys sell their modified cars like pancakes for more than stock ones. Then again on the other side of the stick, there is a '98 E36 M3 with all sorts of Dinan mods listed 'FOR SALE' in the VERY FRONT of the United BMW dealership in Roswell GA (Nice, bright Hellrot red!). (Pssst! Don't tell the dealer they won't be able to sell this modded car, I'd hate to hurt their feelings!!!)
I don't have 'jo-blow' working on my car, or some jerk-off mechanic, I have a certified BMW mechanic (who also used to do pit-work for the Turner GT racing team)working on my car and my 'mods'. Modified cars done by someone with a clue, are just as stable and able to perdict faults with as 'stock' cars, and can certainly outperform in every since of the word a stock car.
A 'stock' car is great, and if you're not a 'car person' that is into cars, making them better, changing them, making it more 'your own' that's quite fine. Just be aware there is a quite sizable (and growing) market for people that like to fool with their cars (And they aren't all teenager hooligans). It's a hobby, and fooling with cars has been a 'Man's' hobby since 4 wheel vehicles were invented.
Don't get down on us for thinking out of the box, and we won't get down on you for being a badge fan.