I am 5'8" and 145lbs soaking wet.I have been on a bike since I was 3 years old. I currently ride a 2003 YZ450 with suspension work, DR.D Pipe, one step up from stock sprocket, and some other small mods insignificant to this thread. I love my bike (especially in Glamis) but recently I have been told by several people at the track I ride it well but could be much faster on a 250 (thumper obviously) based on my size. I am very physically fit and do not have troubles with strength or stamina. The bike is a handfull at times especially in the corners. What do you think? Is it worth the change? What suggestions might anyone have for future changes to my current bike if I were to keep it.Thanks to all in advance.