Track days or racing?
Track days don't matter at all b/c it's not a race. Ride the RC if you want. I've seen a bunch out there and they are sweet sounding!
I don't want to risk or worry about laying mine down so I ride a track prepped 600rr. My skills are far from exceeding the bike's capabilities. Less motor means I have to carry more corner speed to keep up with the bigger bikes and that's a blast, especially when they try to use throttle to make up for bad cornering technique. Passing a 1000 on a 600 provides it's own satisfactions.
The F4i would be a lot of fun IMO.
If you've got time, rent "One Man's Island." It's about a guy who fulfills a lifelong dream to ride the Isle of Man TT and he does it on an F4i.
There will be guys on stronger and weaker bikes who lap you no matter what you ride.
Racing....someone else will have to chime in. SV's are a blast and there are parts galore out there cheap. You might also consider a zook 600.