Bouillion,
The 05 Chassis is a better chassis for pure moto, but the 99-02 Chassis is a good all around setup. I would think the 01 would be a better candidate as the motors are closer in design with the KDX, as the 03 & up have a all new design. Thought about doing one myself but my welding ability is non existent (bubble gum would hold better). Keep us posted on your progress.
DoldGuy