Yep, I felt that as well. Coming from a Hayabusa I missed the bite over 4000, initially.
I did the following within the first few months:
- TORs mufflers (cheap and not loud, and they look just like the standard mufflers),
- Ramair filter (cheap and gives you a little trunk under the seat where the original filter was),
- ecu derestriction (TuneEcu which is even cheaper: just the price of a cable) and
- a dyno tune.
That will make the throttle more lively over 4000 and give you that extra bite. Enough to equal an FJR anytime, at least at the traffic lights.
It will also make you addicted to further improvements, just like me and many others... I have recently bested the RWHP of my old Busa, just by adding CES headers and a tune. Engine has not even been touched (yet).
It's just so simple to let her breath and enjoy loads of added power... and thanks to this forum, you can easily get the info you need for that.