Currently, with the exception of very low production cars from later years, I think only the general population of clean, low mileage Gen 1 and Gen 2 Vipers are appreciating. Ten-twelve years ago, clean, low mileage Gen 2 GTS were selling for $25-30k. Today, you will probably have to pay $45-50k. If the paint is original, that dark blue paint, Sapphire Blue Pearl, was a one year color. That makes it more desirable for a lot of buyers. There were other Gen2 one year colors such as White, Silver, Steel Gray, and Graphite Metallic, but the Sapphire Blue is very distinctive. Interiors were Black or Connelly Cognac. The latter was ordered less frequently, so it is more in demand now. Enthusiasts care a little less about originality than collectors (accepting/favoring smart upgrades), but down the road, collectors will begin to make up a greater portion of the buyers. Rising prices will be a double edged sword, as it will attract more collectors. That will be a sad transition time as we will probably see far fewer cars at meets, since collectors will just want to protect their investment.