myself, brother, and father all had/have 01 cr250s. the mods that i liked best were the vforce reeds(can adjust them for lowend or topend) and bills silencer(wont believe the difference in either mod) the vforce gives the bike more roll-on power because it is basically a reed spacer and the bills silencer seems to give it more everywhere. makes the bike very rideable(bottom end), yet still rips on top end. my dad had thirty thousanths taken off the base on his bike which gave it good low end but killed the top end.