Fast is subjective. On the street, there are all kinds of hazards as well as ticket writing humans in dark cars on the side of the road. You gotta pick your spots and your speed. That said, I felt the 650, especially after a fresh service, quick enough if you whack the throttle through the gears. We do know that little engine likes to spin up and run above 6,000 rpm. I had a 1050 Triumph before that was much faster, but after a while, I didn't really notice much difference between 30 and 70 MPH in normal riding. Off the line and above legal speeds, yes, there was a huge difference when hard on the throttle of both bikes. But in the middle, the little 650 loves that power band it was born with. IMO, not much need in many riding scenarios to have much more, although more can be fun at times too. I'll admit I wouldn't mind riding a liter sport bike now and then. My friends ZX14R was a blast and super well-mannered if your rode it normal. I'd just hate the tire budget on a bike like that though!