I personally would recommend PIAA silicone wiper blades. You never have to change them and the silicone blades actually coats your windshield and makes it act like if there was Rain-X on them. I had them on my Civic for 5 years and the wipers were still as good as the first day I bought them. I'd measure the length of the stock ones, then go to www.autotoys.com (that's where I shop) or some other site where they sell the PIAA wipers and get them. I'm not sure about Mercedes fitment (I'll deal with it when I have to change them) though in terms of the clips. I'll do some research and re-post.
BenzWorld.org forum is one of the largest Mercedes-Benz owner websites offering the most comprehensive collection of Mercedes-Benz information anywhere in the world. The site includes MB Forums, News, Galleries, Publications, Classifieds, Events and much more!