they are a good little motor. i had a 2001 sx500r whitch was pretty much the same sled other than suspension height/ride and skis.
as for more power mods, the reed notch works well on it as does vmaxjhon's 500cc clutch set-up. both are in the tec pages. you could also throw a set of viper/rx/apex skis on it. drops the front 1/2" lower than stock but it will handle so much better than the stock steel skis.
it will never come close to your viper in fuel milage but they are tough and seem to run for a very long time. it will get 9-10 mpg consistantly so if planning on a close run for fuel on your viper, make shure you bring 2 gallons along for it to make the same distance.
