Chapparral 2J
This car is probably responsible for the biggest collective "Why didn't I think of that?" in racing history. Snowmobile engine+fans+rubber strip=ridiculous downforce. These were promptly banned in all higher organized motorsport for obvious reasons. Also, the fact that cornering at a sustained 2 Gs doesn't take well to bumps that break the 'vacuum' beneath the car and thus reducing the downforce by over half...
Again, most of you will recognize the car from GT4, although it was far less obscure than the Auto union car before that. And in GT4, it would kick the crap out of everything on smooth tracks if you weren't stuck with a 2 speed transmission.
Chapparral 2J links
Also, it looks a whole lot like the 'white box' korean concept car that Top Gear made a few years back.
