This guy is selling VW/Audi auxiliary water pumps as if they were the MB version. Though the parts are nearly identical, the hose fittings are slightly smaller on our cars.
The correct part number for MB runs over $200, so people think they are getting a deal. Yes, the VW/Audi version will work, but buyers should be aware they can get that themselves for $90 without being ripped off by this guy, who's selling it for $159:
http://bit.ly/1gH7eR2
Check your part numbers & packaging for anything you buy from eBay suppliers.