I think its do with the brake fade, some one correct me if i'm wrong, as faster cars are capable of higher speeds in theory they will be breaking longer & harder, drums are good but there sealed units = no cool air so there for will over heat meaning your brakes are no longer at there prime.... rear discs are also good at putting just as much brake dust on the rear wheels as they are the front meaning i get to spend even more time on my knees cleanning the turinis :dapprove: