I have found several people who were also looking for info on adding a hitch to their R350. We did so today. As you can see from the photos it is barely visible and did not require large portions of the bumper to be cut off. This is a class 3 hitch (towing capacity 2500lbs) with a 2" ball. After numerous calls to the dealership and warranty division of Mercedes, we discovered (by law actually) adding an after market hitch does NOT void your warranty. We tow a double trailer with 2 jetskis (about 1800 lbs).

 

Read my posting on the R500 post in this same area. I have included detailed instructions on how to install the larger class hitch on an R350...