For what it’s worth. In my opinion you are all right!
As always, anything is only worth what another individual is prepared to pay for a product.
The problem you have with something like this is, it’s obviously a very personal thing, plus to the untrained eye, you would naturally air on the side of caution, if you are not 100% about the esoteric nature of the build.
All these things make the audience smaller and smaller for a commodity like this - Thusly making it a tougher sell!
Personally, I think it’s a fortune for an 8 YO car