Same thing I recommended in someone elses thread:
How far are you willing to travel?
HP Autowerks is hands down the most knowledgeable and best regarding our E82 both 135i and 1M platforms. They actually have a 1M as a shop car which they are going all out with and had a 135i before they got the 1M.
http://hpautowerks.com/
I have also had stuff done at BavarianX whom I would recommend if HP Autowerks is to far, Brad/Lawrence know the E82 platform as well since Lawrence has a 135i.
http://www.bavarianx.com/
Haven't found a good shop in the valley that I have used myself yet though.