I still have no idea about this car and want to share some of my thoughts together with you:
1) The Bugatti 35 front axle shows usually a dramatic positive camber. The puzzle car not really
2) Small wheels with small offset let me think about Bugatti
3) It looks a little bit too wide to me for a Bugatti 35
4) If the cars are lined up in order of the entry list at the starting grid, the car behind the puzzle car is the right one
5) If 'BL' on the registration plate stands for 'Basel', it should be the Ley-car
6) The body lines show similarities with Jaguar XK120