When I got my car/warranty there is a form that discloses everything that is covered. It's extensive. When shopping I asked one guy about this and he said that they don't disclose what is covered until you are ready to buy. The guy was real scum (IMHO). I asked someone else at the dealership and he showed me the Starmark form and said that in additon to the warranty, the dealer also offered their own bumper to bumper warranty for almost anything on the car, except normal wear related items. I've found that to be 100% true. BTW, I bought the car from the guy that showed me this form.
Also on the MBUSA web page there used to be something about what is included in the Starmark program. The page is transitioning to the my2000 stuff and is not completed yet, but worth checking anyway.