I used to have a 2004 BMW 330ci convertible. I really, really loved that car. I sold it when I had both kids in college.
Anyways, I digress. I always had my beloved BMW (did I mention that I loved that car?) serviced by the fabulous folks at Squam Lakes Automotive:
http://www.squamlakesauto.com/
They are family owned and operated and have been so for over 40 years. They specialize in BMW, Mercedes and Porsche repair.