Since you're new here (welcome btw) I'll cut you a bit of slack before the
police kicks in and hammers you.
In TDot a lot of guys go to Ivo @ Columbus Automotive, RMP, and Bimmersport. Personally I go to Darren @ DC Motorwerx (formerly Alphawerx Auto) because he's close by and was a former BMW tech as well. On the east end of the city I know a lot of people like dealing with Street Xtreme and Speedstar.