Cuda prices have definitely gone up, I'd suggest the opposite advice: raise your price. For example, if you go to
www.nadaguides.com, click on Classic Cars, Muscle Cars, Plymouth, Cuda 2-door hardtop, 340, and you'll see your value as:
Low Retail: $13,920
Average Retail: $24,120
High Retail: $43,920
Low retail is in bad condition, enough said. Average retail is a 20-footer...it looks good 20 feet away, but up close... And high retail does not mean show car quality, but merely a good restoration. Right now you're selling it like it's a 20-footer. It's not, right? I'd say up your price to be fair to yourself in 2006 (a 15% increase over 2005).
I don't think ebay is a good example of supply and demand because it seems that whatever car you're looking at, they usually sell undervalued, whether comparing their values with old cars with nadaguides, or new cars with kelly blue book.
In nadaguides, I watched my 1973 Cuda 318 go from $31,700 last year to $36,600 this year....assuming it was fixed up as nicely as yours (I'm working on it every single evening though). Good luck.