i wouldnt say rpm are totally useless. both honda and toyota have engines that are designed to rev high...i know the celica gts/matrix rxs(i believe it is) have the 2zz-ge that redlines at 8100 and fuel cuts at 8400. and my buddies jdm h22a fuel cuts at i believe 8100. rpm isnt necessiarly a engine killer, but you do have be beef the engine up to regularly run that kind of rpm. back in my v8 days ive built a gm 350 for my brother that had a 8500 rpm cam in it...of course there is alot of **** you gotta do to make it run that kind of rpm but its possible and, if done right, can be very streetable