With respect, It is an ambiguous thought.
To a C5 owner ... it’s worth everything.
When selling ...
It’s the common value of “worth” between what a buyer is willing to pay and a seller is willing to accept. Every private sale will be different.
Insurance companies play a different “game of worth” as do Dealership trade in evaluations.
Sorry ... I don’t think you will find a “general value”. My opinion only.