Interesting. I'm having the same issue in my 325i (330i conversion) but I'm attributing that to my aftermarket software. Mine kicks in at about 3500 rpm and will take about 2 seconds to get full throttle when I actually hit the gas.
'06 Arctic Metallic 325i | Sport Package | 6MT | Dinan Stage III suspension | Dinan exhaust | 330i manifold swap! Click here!
| Active Autowerke tune | 135i Brake Calipers | Deiselboost caliper brackets | E46 M3 front rotors