I would recommend Mach V and Funktion. They both cost $$ but the quality is top notch. It has been hard for me to get an appointment at Mach V these days as they are very busy so you have to have patience. I had taken my STi and my bimmers there and never had a problem.
Current | 2011 E92 M3 - Mineral White, Black
Sold! | 2011 E92 335is - Titanium Silver, Black
Sold! | 2007 E92 335i - Space Gray, Black
Sold! | 2008 E90 M3 - Jerez Black, Fox Red