Just saw a neat set up on ebay while flipping through the ATV parts, there was a guy selling a kit to put 300ex a arms and shocks,with the spindle and disc brakes, onto a trx90, and a bracket to put a 300ex front shock in place of the rear shock. Looked real nice and well made, and the 90 he has in the pictures looked great, bet it rides and handles fantastic compared to stock. He also had wheel adapters to put 400ex wheels and tires on, with some cheap ebay parts, you could make your kids old 90 handle like a racer,and look cool too. Too bad my son has outgrown that stuff, would have been fun to mod out one for him.