The post prior to this gives excellent advice and insight.

One point I would suggest is locale-specific though is the claim that Mercedes dealers won't touch in-warrantee vehicles. Except for providing warrantee service (which they don't provide - it's a Chrysler product) my Mercedes dealer doesn't even blink at working on my car. They treat me like all the other Benz owners and give the red carpet treatment. I submit if you are not getting good service from the first Mercedes dealer you visit, try another. They can handle just about all of the drive train issues, probably more competently than the average Chrysler shop (just for sheer experience) and certainly any general mechanical issues - all cars at some level are "just cars". For Chrysler-specific things, you're "stuck" with Chrysler which isn't all bad - again - depends on where you live and which shop you choose. I did some shopping to find the dealer that works best for me - and I'm lucky - the Benz and Chrysler dealers are just down the street from each other.