Have checked tie rod ends and entire front and rear suspension - several times - by very qualified MB mechs.
Am very frustrated with a car that was supposedly designed to run at high speeds on the autobahn, but can't handle 75 mph without shaking itself to death - and all the common responses haven't worked. Why should one have to search all over town for a special Hunter machine to align the wheels? My Honda Accord handled sustained high speeds as smooth as silk - on a regular basis. Not as fast as a MB, but it didn't need babysitting (and has 265k miles vice 249k for the Merc).
Just got back from a run down I-95 to NC this weekend - same story. I'm afraid I'm going to bail out of the three-pointed star ranks.