oddkidd has done this a few times with the mtx from the rs2k
you need cudtom gearbox mounts and mods as above plus something doing with the selectors rods unless you go for the late cable operated boxes these however use hydrolic clutches so that needs sorting too, i am going to fit a foucs rs box to mine which will suit the black top zetec turbo enine too. and comes with a ATB diff alot of work but will be worth it. Sitech racing uses a six speed st170 box on his zvh and reccomends that convrsion.