 I have had 4 window switches put in, 2 CD players, got a leak from somewhere when it rains (water ends up on the floor boards). Brakes wear out early, tires wear out, traction control sensor, and air bag sensor on the same side go bad 2 times.  With 48K miles, the stiching on my front leather seats have come appart.  And we don't drive this car much!!!  Have talked to others with similar problems.  Beware before you buy.  Will never by anoth MB product again.  Oh yes $500 for mass air flow sensor.