Ask around on your local community facebook pages, local church, whatever for a reference. Ask the local auto parts store what the best independent mechanic in town is, and what the worst is. The worst will probably be in your face with advertising, coupons etc to drum up business while the best will quietly exist.
It won't hurt to have a relationship with this mechanic as invariably you'll need a more complicated, relatively urgent service as the car ages that you won't be able to arrange to have done out-of-town at a dealer/ euro expert.
If I were to judge an indy, I'd look at their parking lot. First, are the cars sort of like mine? Secondly, do they have obvious project cars they're working on? "Cool" cars? Third, are there abandoned cars where customers won't pay the bills? The first two criteria are good; the last; bad.
Your post comes across as pretentious, like only a Mercedes trained tech can change oil on a Mercedes, because it's a Faberge egg or something. You also are falling for the fallacy of thinking you can search on the internet for something that's better done with shoe leather in your particular town.
