Sounds like awesome combos. I ride a 97 kx 500, and a 96 250, but i'd give em both up for that 500 in a 450 frame or 06 250 frame. My 500 rolls very nice and has a steering stabilizer, but I can only imagine the improvements that have been made on new bikes like that. Where are you getting rolling chasis from? Are there still crate bikes available out there?