food for thought R : lighter weight, more power, different ignition map, different cam, kickstart only, makes power in higher rpms, different jetting, bigger carb (06, 07- 40mm), different springs and valving in suspension, different flex rate in frame, smaller gas tank, narrower, smaller radiators, no lights, open airbox, open exhaust (doubles in 2006), different gears in tranny, different final gearing. X: heavier, less power, lower rev limit, make power lower in rpms, larger gas tank, different jetting, different springs and valving in suspension, different flex rate in frame, wider, bigger radiators, headlight and tailight, kickstart and electric start, battery, closed airbox, exhaust has baffle and spark arrestor, wide ratio tranny, different final gearing.