I think everyone pretty much answeared the question. Sportbike is a generalized category for just about any bike where the rider leans forward. Those include the race reps, and the likes of SV's VFR's, 919, 599, Z1k, Z750, triples, daytonas.
Race reps are virtually identical to the race bikes used in supersport and superbike. There is some efforts to make them road legal with lights, exhaust, mirrors, and different tires. But for the most part they are what the factorys race. Those bikes offer unparallel performance, but they are VERY unforgiving to riders who make mistakes. The extreme geometry of the bikes that gives them quick handling comes at the expanse of stability. Virtually all will head shake coming out of a corner on the throttle, tank slap from a pothole, lock up the rear tire on a downshift, loop right over from the throttle and have enough brakes to flip over the other end as well. In other words, respect those beasts.