Without a doubt: The Vector W8.
I missed the one that was sitting in Sinsheim, Germany. Got an invitation from museum staff to even take pictures from the inside, but sadly, travel plans for that year fell through, and then the owner decided to sell it.
It had the most gorgeous color of all W8, a dark blue tone that almost looked like black from most angles. Fantastic car. Much rarer than an F40, yet sadly overlooked by many because of the inflated claims of its maker.