Thinking that the vibration was caused by weakened springs in the wiper arm, I bought a entire new wiper arm from MB. The vibration is still there.
Time to sell the benz or drive under 60 mph.

 

Hi,
Have you checked the blade is at right angles to the screen?
Have you checked the blade "stops" at each end of the wipe? If not this will cause "Judder".

I still don't know what you mean buy vibration especially since you seem to link the problem to speed!
The wiper should work fine at well over 100 mph.

Have you checked the wiper motor mount is OK. usually rubber. may have perished or possible it is not correctly located of someone has had it in pieces. MB mounts ofetn have a mechanism to allow you to adjust the mount so that the blade sits square to the screen..

Are you sure the screen is clean and not contaminated with oil or cleaner (other than glass cleaner)?

Please be assured that something is wrong. You need to look at the installation carefully to determine what is wrong. No need to change the car. Everything is replaceable.

Stuart