03 and up are the best because they fixed all the major problems and made some improvements. like cam chain tensioner, clutch is better, no more starter kickback. 01 is the bastard child stay away from it 99-2000 are all the same electronics and parts. 02 and up are all the same electronically only thing that changed there is the 03s had the starter fix. 05 and up had the passing lamp button which is nice for nitrous activation.