top speeds are limited mostly due to the speed rating of the tire. most have a h-rated tires, which is safe upto 130 mph.
zhps have z-rated, which i believe are safe upto 155 or so.. either tirerack.com or tires.com has the complete listing for speed ratings.. you cna prolly update the software to either shut down or increase the speed governer.
nice pic khengswee, hopefully you didn't "dzervit"-ed it..