Michael, so you must be putting down 280+kws ATW with your car. That being the case an M3 was and will always feel slower than your car. IF you want an M3, and I recommend one, you will have to spend to buy it and then the extra cash for a S/C kit, if you want that kick as you have been accustomed.
Your seem to be in the predicament many of the 1 Series guys are in... why buy an M3 when it is "slower" in a straight line, has ~100nm less torque EVERYWHERE, costs so much more and is not easy to tune, without big dollars.
Depends what you want mate, I loved my E92 even though our shed also had a 1M sitting next to the M3.
If you want tunability, get a 1M or maybe waht some of the guys on 1Addicts are doing, an R35 (not a fan myself)..
Good luck mate.