Just FYI, I've never seen one of these models, although I think I have seen pics of a gold plated-looking Viper in 1:43 scale. I also have never heard of that company. So it does appear those cars are hard to find, but I honestly don't have knowledge on its collectability.
I collect a lot of automotive model cars. I collect mostly 1:43 and 1:18. I have a bunch of Johnny Lightnings, ranging from Vipers (I have ~ 10), to hot rods, to muscle cars. I have about 60 1:18 scale cars (11 Vipers, a few Porsches, Ferraris, Lamborghinis, Fords). I do most of my collective shopping in Toys R Us, K.B. Toys, and now branching off to a hobby store since it's close to home. I may be going there tonight and I can see if I can dig up any general information for you and the rest of the model collecting world.