Tried the Potato, didn't work and looked like a mug.
Dealer put a new arm on, didn't look to me like it was much better.
They then changed the blade to one that had a mercedes logo on the end of it and it was perfect then. I noticed someone on another forum had their problem fixed when the wiper used had the mercedes star on it. I don't really know why, and the original wiper blade was from the factory as the car is pretty new, but there you go. Maybe it's a slightly different quality of compound. http://mbworld.org/forums/c63-amg-w204/386231-wipers-3.html#post5615385
Same issue. Wipers are very smeary. Usless. Had it to the dealer and they reversed them with no effect. No real interest from merc Aberdeen on a new c63. I've never hated a dealership so much.
Sliced or diced carrot brings images that I would rather forget. Helicopter bed. Sweaty brow. Projectile vomiting. Yes. The hazards of eating a dodgy peanut on a good nights drinking.