I've been eying the Upsolute tunning. 400 bucks and they tune to the mods you have on your car. Also, like a 15hp increase, more if you have an intake and exhaust.There is a spot in Orange County that did it.
M-tech E90 330i JB/TERRA modded - RIP
n54 135i AW/CR JB3 FBO 420whp 444wtq - 11.5 sec 1/4 mile @ 122mph - RIP
e53 X5 4.8is M///BLUE/M///SUEDE - 357whp 369wtq - The Snow Beast!
n54 135i JB/CR JB4 FBO - Tc Kline D/A Coils - 1/4 mile/dyno PENDING