i use porterfield R4S on the street and love them. have had the same ones on for 2 years and they still have atleast another 2 years left.

for the track i've used panther + and ferodo ds3000. braking power is about even, slight edge to the ferodo's. cold bit sucks on the panthers and is great on the ferodo's but the ferodo's seem to be much harder or rotors than the panthers. my autozone track rotors have seen 4 lapping days with the panther's and still looked new. after one day with ferodo's there are stress cracks in one of the rotors. i'll probably switch back to panther +'s or move up to the XP's