I think I am probably one of the only folks to make money on his Viper. I paid $70,700 for it in '98 and I sold it for $72,000 in March of this year.
But that was an isolated case and I lucked out. The ONLY time a Viper would be worth more is first of all a looooong time from now, and second by dumb luck. They made too many of these cars to have them really be worth money. Even if some of them do appreciate, it will highly depend on what model... might be the ACR, or the GT-2, or the blue/white GTS, or the '92 RT/10, or the '97+ RT/10, or the final editions, who's to know?
If your car ever gets rare enough to be worth some money, it won't be for a long time and the mileage probably won't matter so much if it gets that rare, so drive it (and drive it hard)