I've just fitted a TSR250 fairing to a MC21. It requires quite a bit of carving to clear water hose, exhaust (Dog Fight) - rear RHS and Front LH cylinder, and under the nose to clear fairing bracket. I also bought the latest RS250 seat which fits OK but the standard under seat tray with battery, PGM etc. hangs out the bottom - looks crap. I would suggest an earlier seat like the road model ('97?) if you don't want to relocate/mount all the stuff under the standard seat.
Stuff was from Race Products in Market Rasen Lincs - very helpful and good quality with mesh not mat reinforcement.
Mike