it is relatively easy to make it fit,all you need to do is make a small square frame,thats as wide as the spars on your frame,fibreglass it underneath the unit, then weld 2 nuts behind the gromet holes that hold the origanal plastics, halfway down the seat, and get 2 f**king long bolts, and, then cut the back to let the rerar light in, and jobs a good'n.you would probably want to tidy it up where it meets the tank, but i havent find a tidy way of doing it yet,but it doesnt matter when your sat on it.might modify the original seat pad to merge in with the pad on the new seat,then it wold cover the untidy bits.
sounds like alot of work, but it really isnt, as it all lines up quite nicely,and gives you something to habg on to with your legs, when your really hanging off it