What are these rotors made from? I've heard that with lighter rotors you can really spin the Eaton alot harder because of the weight reduction. This could be the reason for the 2.65 upper and 4lb. lower? How many pounds of boost are you seeing?
If i remember correctly from ttk53s threads they have a bit more twist to them that the standard m112 rotors, i dont remember if they are lighter or not.