Les has more track time than I do but I am a fan of the Porterfield R4S. I would compare them to stock pads on the street with less dust. Never had an issue with them in the cold but I am in Atlanta and we do not have bitter winters.

On the track the pads have done well. In running them at Little Talladega, Road Atlanta, and other tracks I never had an issue with the pads over heating and I had lap after lap of slowing from ~145-150 down to 35-40 and no issues with the pads. The stock rotors did overheat and I did get some shuddering.