Funny I'm in the middle of installing Curt hitch on the back of my 04 E320 wagon. Picked it up on Amazon warehouse for $50.

In the UK the 211 wagon with an automatic transmission is rated to tow 1000kg unbraked and 2100 kg with trailer brakes. Curt in the US says their hitch is rated at 2000 lbs but you shouldn't exceed the car makers tow rating which MBUSA will tell is ZERO lbs. I'm going with 2000 lbs.

The hitches they sell in Europe for the 211 are a completely different design than what Curt is selling over here. The Curt relies on a couple of U bolts attached to the bumper supports. The Euro design replaces the bumper supports completely and attached direstly to the frame of the car.

Wiring up to this car is the same as the 210. Any powered trailer wiring kit will do the job.

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CENSORED due to not family friendly words