Alright guys so i am almost 16. 140-145lb 5'10 and mainly ride a 2012 KTM 300SX. i can handle this baby pretty well and I'm looking to get another bike just to mess around on and maybe race some classes with it. Would i be able to handle a 450f? Or should i just get a 250f? I know my bike is pretty fast , but theres a weight difference and power difference and I'm not sure if i can handle it? I don't want the bike to be harder to handle then my main one and i don't want another 2 stroke or bike that has no common grounds between my KTM. By the way the bikes will be from 04-07 help me with models if you can as well! I was thinking either a kx250f/450 or rm-z250/450?!