Ive a 600f rat with a b12 engine in, You need to shim the rear engine mount bolt, fit the 600f rocker cover breather box and ditch the petrol tank support brace for the engine to go in. It'l run on the 600 loom but obviously the rev limiter isnt going to be in the right place. Other mods wise, gsxr6 k4 rear shocks drop into the teapot and make it handle a shit ton better, gen 2 teapot rear wheels fit wth minimal work aparently and can handle a bigger tyre size (although ive not done the rim swap myself so I cant be certain) Ive bodged a gsxr400 gk76a front end into mine (badly, it shouldnt really fit) and nissin 4 pots are a suitable addition to the front if you do b12 it, rear brakes wise Ive not bothered to upgrade, the 6f rear brake is capable enough of locking the rear with decent pads in so who needs more. Cheers VJ