Have you tried selling one recently? Sorry but I'm inclined to agree with John. Depreciation is just a fact of life when it comes to cars. There will always be a niche sector of the market, but the vast majority of owners will just have to accept their car is not worth as much this year as it was last. The ever increasing cost of running 3L+ sports cars is only going to compound the fact. As for single builds being worth more, think again. They are a money losing exercise for the most part and you will NEVER recoup the money you spend on mods. But then you do it for the enjoyment and not for the investment.