I have had my M635 too short a period to make a recommendation, but I have a good German-stock friend who had a 635 in Atlanta for quite a while until recently, and he is thrilled with a mechanic in particular that I can't recall now. My friend's name is Glen Sprouse. His home phone is (770) 804-9593. Glen knows a good bit about 635s and he is always thrilled to help a fellow enthusiast. Glen also is an incredible brewmaster, but you can get that part of the story from him. Good luck! O'D