Power isnt everything these days. With how well the KFX handles, you shouldnt have any problem keeping up with any other 450 out there. Slap an intake, programmer and a 15t front sprocket and i bet it will beat the YFZ of yours.
2008 Green KFX 450
16" Dasa Pipe,PClll USB, Fuel ATV Intake, KX Cams, Gibson LT A-arms, Fox Evols Fronts, Motowoz Rear, Rath Nerf Bars, RPM Dominator ll Axle, Precision Steering Stabilizer, Maxxis Razr Cross Tires, DWT Rokout Front G2 Rears, Houser +1 Steering Stem, Tag Railer, Fasstco Bar Inserts.