I just smoked a modded 450 last night. It was piped, ported and was on race gas. He weighed 160 I way 240. Mods on my bike T5's, Fast dune port, 28pwk's, pro design cool head 20 cc domes, stock cages aftermarket reeds, timing plate plus 4, pod filters. He could hang pretty good until fourth gear but from then on I put about ten bikes on him. The 450 seemed really quick but lacks top end imo.