Love your car. Nice choice.
I tracked my n54 335 with success until I upgraded to an M3. I did it with a very simple set of mods:
1) Driver training
2) Coils, alignment
3) Tires (I used 19" Mich PSS since it was my daily driver)
4) race pads + fluid
5) tune + 50/50 water/meth system (water/meth keeps IATs AND oil temps down) + catless downpipes. I never had to come in early from a track session because of heat soak. Plus, my car would start pulling on cars in the 500 to 650 HP range in the mid to late session as they are pulling timing from very high IATs and I am not due to the water/meth. I used the Procede adjustibility to create a linear boost curve that mimicked the power delivery of a N/A motor.
6) Wavetrack LSD