If price is a consideration, C32, c55, CLK55 all use the same brakes but they are more rare and expensive. If you are willing to run SRT 330mm rotors you can run the same type caliper from a S or CL class which is much more common and can be bought cheap. If you click on the link above and look at the pictures of the C32 caliper for sale you will see a little offset where it bolts to the spindle. The S and CL class doesn't have this offset which is why you must use four flat washers to make up the difference. Other than that it is plug and play. I have this set up and it works very well.