I've owned plenty of cars and have never had a vibration problem that couldn't be simply resolved. I've had both American RWD autos and foreign fwd cars. I currently have a 1987 Maxima with 200k miles and is as solid on the highway @ 75mph as it is around town. It's had its share of parts replaced like tie rod ends, struts, ball joints, cv joints, etc., but it didn't list for $60k and it didn't have these problems until atleast 125k miles. I've never had a bad wheel or tire and have been getting them at the same place for 15yrs. So what's the mystery with this Mercedes? Tires, wheels, bearings, and front end have been looked at over and over again. I'm now looking at exotic things like rear axle, drive shaft bearings, u-joints, flex disks, cv joints, and differential. Can a car that cost $60k new and only has 75K miles and that hasn't been abused (not a beater) have these issures and which one is most likely???