My dealer is a Dinan dealer.
I would only consider doing it there, and it was actually a reason I purchased from them (besides the aggressive pricing).
If I moved, I feel like I could get screwed.
2012 335i Mineral Gray
JB4|M Performance Exhaust/Brakes/Suspension/LSD|Bav Stage 1/AMP||ER CP/IC/DP | Dinan CAI/N55 PWG BIG TURBO|BMWF30.com