Always buy directly from Mercedes if you can. I've tried these second hand
warranty places, and when it comes time for a fix, they always are trying to
look for a reason around it or not to pay. Right now I have a 98 E320 that
I had Starmarked when I bought it and when I take it in for a warranty
covered problem, I get no hassle at all. Drop the car off, pick it up,
don't have to pay a dime. So, buy from Mercedes. When it comes time to
work on the car, you'll be glad you did.