First off
Since you went from a torque monster 5.0, to a 2.3 I can see why you think the response is slower. I would guarantee you that unless your 5.0 was modded, the response in your bimmer is way quicker. You're just used to the torque of a 5.0 liter engine compared to one that is less than half its size.
Auto or Stick?
Pics?