Teddy's Foreign Motors in Somerville, Ma is my recommendation based on my experience. I have an '81 300D and this guy knows my car inside and out. "Been working on these since I was a kid" was what he told me. Will do as little or as much as I wanted done on the car and the price was very reasonable for what I had done. In my experience he was a very honest and respectful guy and at no point did he have that "I know better than you" attitude. But I'm sure everybody has their bad days. Used to be in Belmont on Trapelo road but recently moved. I think this guy really knows his stuff but I guess you can call him and talk to him for yourself to see what your comfort level is. I wish I lived closer to him. I'd give Teddy all my business.