I also must put in my $.02.
I have had only one lemon of a car... 1993 Ford Taurus SHO. I bought it new and within the first 60,000 miles it was in the shop 22 times. Mostly for electrical system problems and faulty O2 sensors. There was numerous factory recalls, but none of them major. I constantly complained to the dealer and to Ford about the lack of confidence in the electrical system, but they just kept 'fixing' what broke down. I received 2 driver's power seats, 1 passenger power seat (whole seats), 2 starters, 1 driver's power window module, 7 O2 sensors, 1 wiper switch, 1 wiper motor, 1 climate control module, 1 complete moon-roof and required electical....... you get the point.
The dealer fixed everything right up to the warranty ran out, after that, I was on my own. Three months later, a little old lady tried to drive her Oldsmobile THROUGH the front end and driver's side. The car was totaled! And, as I expected, the air bags DID NOT DEPLOY due to defective sensors or wiring. Ford takes no responsibility for the faulty system because of the history of electrical problems of this car and being out of warranty. Oh-well, that's why I have a lawyer!
Bottom line, complain in writing to the dealer's general manager, the owner of the dealership, and to MBUSA. Document everything, and I mean everything! Keep after them and sooner or later they will give you a car to make you go away.
Recently my father's new GM truck had some kind of transmission failure (for the second time in less than 6 months). He called and wrote to everyone including the president of GM. Now he is driving a new truck with leather -- no extra cost!