Downside to M3 setup in 330 4dr?
I recently swapped out 85k oem 330i suspension for 25k OEM M3 suspension. Everything fit fine and went in smoothly. Car ahdnles much better (also added turner sway bars)...
Yet, some folks in other threads maintain this is a bad idea that will not work out well...
Why not (other than argument, wasn't designed to...).
I'll tip my hand and say I have been told by BMW cert mechanic that it's totally fine/safe/effective approach..