I agree, the modified cars, tributes, clones etc... will maintain a respectable value but you won't see crazy numbers. For example, my 74 cuda was completely restored, has the billboards and color I love, may not have all the details to clone a 71 but is what I like. Nearly everything is new, I can drive it for what I need, I couldn't build it for what I paid and I gave about 28k for it. This price to me is driven in part by what you can find comparable. For example. Could I touch a REAL 71 cuda in that shape for that price? Not a chance in hell !!! What are new "muscle cars" going for? Decent ones are pushing 35-40k but to me are completely different that the "collector cars" we're talking about. So I think these "clones" or modded cars will follow the same curve as the high end cars but not nearly as extreme. Basically, if the numbers matching cars go up I think the clones will go up. However, where a numbers car may go from 80k to 100k a clone might go from 28k to 32k. The clones and modded cars are there for the people who love everything about the originals, understand what they're getting but can only afford the full experience of owning one without the papers and tags. Not saying I wouldn't love to have the paper and tags but I'm still in the middle group who are just entering the collector market. I'll be the one driving the prices up again in 20 years lol.
