I've been going to Paul's Motorsports. He's changed pretty much every fluid there is to change in my car and he fixed a tail light issue. He's prices are good compared to other indi shops I've had quote service and it seems like he's very knowledgeable about BMW's (he formerly worked for a dealer). Fortunately however, I've never needed to have him troubleshoot anything more than the tail light (that grounding issue with the older tail light assemblies).
https://paulsmotorsports.com/