really man bolt ons are cool. but if you really want that custom one off look make your own or look around on ebay .and check out different bikes seats like gsxr or yamahas or whatever ,and make one work its called customizing sure you can take a f4i rear sub frame and swap it all out but it will still have that stock look the newer r1 rear are really cool and would drastically change the look of the bike . you might have have to modify your subframe but its all cool