I'm 15 and coming up on the end of my first racing season. Lately I've felt I'm actually capable of using most of the bikes speed (there are still things I can do to be faster of course), so I'm wandering if I should keep the 400 and get faster on it or go ahead and get a 450 now? I've seen ALOT of people say a 400 isn't at much of a disadvantage in XC if set up correctly. I recently picked up my first sponsor VANILLA GORILLA RACING and am really excited to see where I can go with racing. Thanks for any advice guys.