Front Shock Bushings
 

My 1989 300E has 210K on it and I think they have Monroe shocks on it. It doesn't bounce up and down but when I hit a bump or cut in the road it jars the whole car. My Ford truck rides softer that the MB. Could it be the rubber bushings holding the front shocks on the top? Or replace the shocks.

You can examine the "strut mounts" on top and look for separation in the mount the rubber will be cracked almost all the way through. It is not that tough a job, within the scope of a backyard mechanic.
Severe harshness in the ride could also be the front A-frame bushings, lower ball joints, or you may feel losesness in the steering linkage, with over 200k mi. The A-frame bushings are better left to a pro.