IF you have the cash, go with the eline/baja designs 200 watt stator, i have one on my 02 cr250(eline stator and baja designs 8" round headlight) and good god, its like having a car fallowing you its so bright. ive tried the wimpy 60-80 watt "add on" stator coils and they dont even compare. im running 90 watts of lighting right now and still have 110 watts to spare!!! not only that but if you ride mostly trails the external stator uses an add on flywheel magnet for an additional 13oz (i think) of rotating mass on the crank
also keep in mind, when the stator mfg.s state a wattage rating, its wattage at max rpm. so in the low end of the rpm band, a 60 watt stator may only be putting out 20 or so watts