I'm guessing it has a 180km/h speed limiter like most Jap cars seem to. It could probably go faster than that if you had a way of disabling the speed limiter. (Fastest I've been in my Jazz vti is 160 on a long empty freshly sealed road in outback QLD.. the car felt just fine at this speed)
If some of the Sydney guys here come to the Ozhonda Wakefield day, maybe we can find out together :) (though, the straight isn't really long enough to do more than 180ish)
http://www.ozhonda.com/forum/showthread.php?t=10329