well hummmm how much money you have ? you could do Engine Internals. [ Pistons / Cam shafts / Head porting ] not something everyone can do , i know i cant :) avg cost your looking at 500- 5000 dollars you could slap a turbo on it :P 3500 + bucks Nitrous ?
those are the other performance mods i can think of atm
Seriously, the F4i is still a very fast bike. Engineers spent alot of time and work designing your bike for the best performance. If you really want more speed than 150+ mph. Save your money and invest into a 1000RR or even a Hayabusa 1300. But I personally don''t go over 100 very often, its fun but I know I can do it. Most of my fun is zipping around town.
Ya def suspension upgrade before touching ur engine. But u can spend 5k alone in that. Look into making her better not more powerful cuz ur bikes gotta be able to handle the power u put into it
