If I felt I were truly selling a unicorn and wanted top dollar for it, then regardless of the make or model I would ALWAYS choose to sell it on https://bringatrailer.com/
People with true wealth monitor this site because they know cars "that no longer exist" are offered for sale here every day. The buyers on this site have money but not the hours it takes to scan the internet looking for a needle in a haystack. This car comes the closest to what you have and thus might be an indication of the sandbox you'd be playing in. Notice the photos of the undercarriage. It is unbelievably pristine.
https://bringatrailer.com/listing/20...r-crossfire-4/

Here's another (NON-Crossfire) example of the cars this site seems to find, and in this case, what seems to me like an ALL TIME RECORD PRICE for this make and model. But again, look at what is for sale. I don't say this as hyperbole: I saw unsold Alfa Spiders on the dealer lot in late 1994 with more rust on them than this one! https://bringatrailer.com/listing/19...omeo-spider-4/ It's truly an unbelievable time capsule. I wish I were still in MY 1994 condition!