i dont buy into no warped rotors...having been a mechanic for some time and having to "turn" probably close to a thousand sets of rotors...i just dont buy into them not warping..i have done rotors on many many makes and models of cars with many many types of brake pads from cheap to extremely expensive...when you dial in the brake lathe you have to cut into the surface at a slow interval to determine the depth of the warp....from my experiences with metals, the pattern associated with warping is consistant to what happens to metal that has gotten hot....also the actual metalic composition of the pads is of course different from that of the rotors, if they were actually transfering material to the rotors it would be noticable when you turn the rotors on the lathe, related in terms of the pitch of sound the lathe makes as it would pass over the different materials...this however is not the case...the pitch doesnt change at all. if you've ever turned a rotor you wouldnt buy into "no warping" either...its pretty easy to see that the rotor itself is in fact able to warp under extended high heat conditions...