Don't know if the earlier wheels(pre-07) fit the later chassis. If so, my '00 XC had a 19" MX wheel from a '95 KX 250. It slid right in with the KX spacers, but ultimately wasn't precise enough for me. I know I made shims, but never wrote anything down. When I sold the bike(after a bad crash) I kept the KX wheel, since was part of a set. I do know, on a scale of 1-10, the difficulty level was a 2. It took about an hour to get rideable.