The FZ6R engine is pretty flexible, I ride 5th-6th mostly on backroad carving, and seems like plenty of power even on tigher stuff with no hint of bogging.
Straights see 7-10K in 6th pretty regular; I call it a 100mph bike, gets there super easy, past that takes a bit longer. And, really, I am not really interested in top speeds anyway, the corners are where the fear and skills come into play.