The mass air sensor was replaced in my wifes 2000 C230K about 2 years ago with 16000 miles. The C/E light came on and the supercharger wouldn't engage. At this time my service rep. told me that it wasn't uncommon with the C series as he had replaced approx. 30 of them the month before!!
Fortunately that was the first and last time it was replaced, the car has 47k miles on it now with no problems since. KNOCK on Wood!!!
It really has been a great car with loads of part throttle power and great gas mileage.