Thankfully no, but I have read about these problems on the MB forum. I think given the relatively low mileage of 64 500 km and the fact that the car rarely revs above 4000 rpm means it hasn't really been stressed that much. There isn't much opportunity to do so. However I have started to floor it once or twice a week when I drive it, just to loosen/clean things up.
I really think the W211 is underrated, despite some areas of cost cutting it is still a proper MB tank like the old days, both for the exterior and the interior. This is especially evident compare to the current generation of MB.
I will probably spend some money on the car this coming year, wanting to get the slightly bigger 17" wheels with the same style and perhaps fix the COMMAND unit.