whatever pads you go with just don't go with Porterfields
i had them on my c36, great breaking but warped brand new stock rotors in less than a week, not to mention screatching loud when hot, swaped them out for stock pads and of course brand new rotors again since first warped.

i should have learned my lesson, when it came time to change pads on the X, what i do? i get porterfields rs4 pads on new stock rotors, what happens EXACTLY same thing as on c36. so i think maybe stock rotors are too soft, i put in brembo rotors what i get SAME thing warped less than a week, same loud sound (old breaks squicking sound) embarrasing. So off i went 4 new rotors, pads stock this time again. Yes lots of dust, a little loss in initial bite, a little loss in very high speed breaking, but no freaking noises.

sorry just had to get that off my chest each set of pads was like $270 not to mention any rotors costs, i was a little dissapointed to say the least.