For exhaust I'd look into a Keda RT-XB-1 you'll need to tune your bike but you'll be looking at around 10% over stock on hp and torque. He did some testing with my 9r and the air/fuel ratio was around 19.5:1. So it needs a lot of fuel. But it made 1 less hp then the race pipe.
After you decide on an exhaust you could do the open air box mod and breather reroute.
Without spending a couple grand that's about were the performance mods end.