<< Actually, for a 1996 Viper RT/10 $55,000 is on the high side.
Not including the modifications, KBB value is under $41K.
Viper GTS >>
Modifications will DEVALUE a car. Mods will only raise price on car if there is a market for it. But if a dealer takes a modded car for a trade in, it will be less than KBB.