I have a rare opportunity to build a cool street machine. Does anyone know if a 04/05/06 WR450 motor will fit into an 2003 YZ450 frame? Any idea what the differences are in the frame? I would have two complete bikes so additional small parts are not a problem. I thought about the tranny swap option, but considering the cost/benefits, why not get e-start for a couple bucks more! If anyone knows where to find a new leftover WR that would also be cool. Thanks.