i have several friends that ride 450's. 2 race cr450f's every local race we have and constantly practice and i have yet to see either one of em EVER have to roll start there bike, hold the hot start and fires right up. have a couple friends with 450 quads and i have yet to ever see them roll start so i dont know where anybody has come up with that joke. the same quads trail ride and i never see them overheating. as far as the oil changes that regular maintanence anyway, your plain ass dumb if you dont change it often, if your racing hard you should be changing more. i also have never rode a 450 dirtbike that i ever thought needed more compression or more power, they come stock with so much power thats it already stupid fast. i would rather be wheelieing than spinning anyday....guess you havent heard if you spinning you aint winning lol. racers are riding 4 strokes for a reason. when you are making a living at racing you are gonna put yourself on something that is giving you the best chance to win and you see what everbody rides that says it all.