I installed the R4S brake pads with brand new Brembo OEM rotors on my ML55 last week and I have been runing with them all weekend. I took a trip from Miami to Daytona and back. So far the pads have done their duty. They have far less dust then the OEM pads, the braking effort is better then stock only when after the brakes have been heated up a bit. You actually need more effort to stop the car when the brakes are still cold. They make a slight hint of squeek when they are still cold only right before you stop. All and all, so far I am really satisfied with them.

Im running the R4S pads on oem rotors,for about 8K miles now.Very satisfied with the braking power.Dust is no longer a problem. When they were new,I had a slight squeal like you described,which subsided with more accumulated miles.Definitely would buy them again.

Where did you guys buy them and how much did they cost?

I got them from Jerry at formymercedes.com in case the link doesnt work below.


http://www.formymercedes.com/porterfield.asp

got mine at the same place!!! I highly recommend www.formymercedes.com

fast efficient shipping and great customer service!!!