Car Tender on Capitol Hill in Seattle--they do almost all of their work on BMW and MB. Not the cheapest shop in the world, but the guys who work there really know what they're doing, and they're willing to tackle older cars, etc. Quite a while ago I had a problem with my Nissan--the dealership said they didn't know how to fix it, but CarTender had a welder on staff who did the job. Also, they didn't mind when I drove my largely dismantled car in there (I'd already removed the dash, instrument panel, etc.), and asked them to help me out with something that was far beyond my capability. Pretty cool.