Do not go to Motorcepts. This was my experience a few years back, I doubt it's gotten any better since a few friends have had similar less than stellar experiences recently too (as of earlier this year).
https://f80.bimmerpost.com/forums/sh...2#post22007982
I always vouch for AutoCouture because I've had extremely good experiences with them. They tend to be on the pricier side of the echelon, but it's better to pay up to get things done correctly the first time rather than taking it to some place with an ok reputation and having to do it twice or have your car in shop for extended periods of time. I speak from personal experience.