They specialize in BMWs, and really, really know their stuff. They are honest mechanics (an oxymoron you say???), as I once dropped my car off because I thought I smelt something odd (maybe it was just my passenger?:) but they called me back a few hours after I dropped it off to say that nothing was wrong, and I wasn't charged anything. When was the last time you heard of someone having their car in the shop for the day and not being charged anything???
Only thing that prevents 5 stars is that they are so busy it can be tough to get in. But, such loyalty from their customers speaks volumes.