This continues to be a source of much discussion, but wanted to offer up my recent sales experience involving my 1972 911T Targa.
http://forums.pelicanparts.com/porsche-cars-sale/569599-1972-911t-targa-sale.html
I think the description is pretty fair. Full of history, line by line parts, a few flaws, etc. Right from the beginning, I describe this car as a non-original vehicle. This automatically turns away probably 50% of the available purchasers. I do have several tech articles and projects listed on the board, so someone willing to do further homework could find further information.
Within 4 hours of posting this ad, I was on the phone with the future buyer. 2 hours later, I had a paypal deposit. 2 days later, I was paid in full.
This car went for the full asking price. No dickering. No PPI. I also had several other inquiries, that I never had a chance to speak with in person.
Over/under? I don't know. You guys like to say a car is worth what someone else will pay for it. But it seems to be a good reference for non-stock vehicles with full descriptions, vehicle history and board references.