I wonder this car was not already added. This is the original Opel GT. And it was a cool little sportscar.
Look at this. It looks like a baby-Corvette! Haha! GT was such a maneuverable and swift car, so much fun to drive. Even though its engine was not too much powerful, the car was light enough to accelerate to 100 in 11.1 sec and achieving 184 kph top speed. Respectable numbers for 1968.
All the data come from here: http://www.autozeitung.de/classic-cars/audi-100-coupe-s-opel-gt-bilder-vergleich-ausfahrt-gardasee-gn20230?page=0,2
Imagine what could happen if someone decided to put here a big block GM 427 engine! :D