Ah, yes, it was tires after all...it seems that tire quality today is pretty poor. It doesn't matter how much you spend either, and in fact, it seems the more you spend the worse the tires are. I am running Michelins on my E300 now (MXV Energy +4) and am very happy with them (so far). They have about 10K miles on them and still look about as they did when new and the ride is very smooth on the highway...not a hint of shake. I criss-cross rotate them every 5K to make sure the right rear doesn't wear prematurely as it did last time.

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz