Just got back from Brullen...
The place was okay, the person who helped (Richard) was very informative. Well either way, in case ppl want to know the prices, for an M3, they are going build a full system that you customize for about $1500 plus tax. Apparently their exhaust system can increase the HP of the car, but he says that they are only one of two companies to be able to make that claim (they have dyno to prove it). If you want just the muffler, then its about $1200 plus tax. Those prices are for full installation as well, seems reasonible. Nonetheless, thats about it.