I've never tried Porterfields, but heard good things about them from racers. The stock rotors are two-piece rotors and the calipers are a floating design. Many MB Master Techs have told me these were closest thing to racing brakes that AMG designed....hence the cost. Most AMG brake setups are now fixed calipers and the cost is significantly less.

For example: A WHOLE C32 setup (pads, rotors and calipers) can be had for less than $900 if you shop it....our front pads ALONE run $300. You gotta 'pay to play', I suppose.

Look up the specs on the C32 brakes vs W208 CLK55 stopping distances. The CLK stopped from (60 mph) an average of 5-7 feet shorter than the C32 with the cross-drilled setup and non-floating design. If you get a chance, examine the rotors and calipers between these different setups....the changes are very plain to see.