I have a friend with e63s, and I already lost count how many times he has been to service for major issues. Transmission doesn't shift properly to this day, and Mercedes replaced his real diff twice (car was all stock). Now he is struggling to tune the car properly, as some 3rd ecu keeps interfering with the tune and erases it over time.
Me on the other hand with my F90 M5 ***knock on wood*** I haven't been to the dealer once for anything major, or any warranty repairs to be exact.
I do like to listen to his car, on those rare occasions when he is not driving the CLA loaner from Mercedes service
