I also used to burn through a set of rotors every 2 weekends when I had stock cobra rotors. Now I have cobra calipers but I upgraded to Craig's old set of 2 piece rotors when he went to AI, 1 set of rings has made it all season (had 2-3 on them when I bought them) and pad wear seems reduced. I have ducts (but not good ones). The pimpy 2 piece rotors do make a difference.