Mercedes service shops north shore (non-dealer)?

I would take it to a private mechanic that you trust. I fixed a Mercedes alternator when I worked as a mechanic. It was on a 1991 300E but it was quite a job and the parts were the killer -- list price on the alternator was $600. But any competent mechanic should be able to do this job, no need to go to a dealership which has screwed you in the past.

Thanks. I went to Advanced Auto Clinic on Lake Avenue in Wilmette, owned by great guy named Sam who has a penchant for cigars (as early as 7am!). Anyways, he was extremely reasonable, gave me an option for a Bosch alternator at half the price, and did other checks on the car for no fee. Alternator was $380 and he charged me $140 or so to install it. He even gave me a loaner to use for 2 days. Probably the best service I've ever had on a car. Just found him in a phone book and now his #1 fan.