Vibration on the E1/E2 (00-01) ZX-9r is at its worst at 60MPH/4,000 RPM. I've ridden other bikes, and this is somewhat of a relative overstatement. The ZX-9r vibrates so little, going almost completely smooth between 70-78MPH, it makes it an ideal highway touring mount.
My opinion? Best sport-touring mount out there: range, power, comfort. Properly tuned it will, in one way or another, smoke the sport, sport-touring & touring bikes, with a MPT range (mine)
266-275 miles*. Sticks with the more powerful and lighter liter bikes in the canyons, but
it's all ZX-9r after that; leaves them in the dust on range and comfort.
Dry weight
~403 lbs.
* Note: From a stock setup with minor changes being air filter, slight jetting adjustment, & replacement of stock exhaust. 9s rejetted and re-geared lower can drop these numbers to 30 MPG/150MPT. Stock is about 235 MPT.