I believe i was the first one to race a M3 with my tuned 335 back in 2007 .
the car that raced the Gt3 is my old one.
The worst enemy of the N54 motor is heat, so go catless with the Dp , buy the biggest IC you could find, and a meth kit, i wouldn't recommend the JB3, two Jb3 motors has blown the last year here in Sweden,go for the procede V4 or maybe Jb4.
But that will be a great car with a lot of torque
M3 E92 ESS VT-625