I won't be stupid enough to reveal my methods (which would never, ever, be GSI) but it was quite easy. Just a few key words and the web provides references to Austrian eigenbaus, and the car was included in some race results. A quick check with Google Images gave me the photo I included in my post.
As I have just posted on the Reed Citroen puzzle, I can't understand why others can't do this. If I can do it, and believe me, I'm as adept as a lobotomised chimp with IT, then surely other members could have a stab.
I had already guessed some of your puzzles were taken from magazines - no wonder they take so long to solve!