Three years ago, at the Paris Motor Show, Audi showed the Quattro Concept, a two-door, all-wheel-drive supercar commemorating the 30th anniversary of the first Quattro all-wheel-drive coupe. Although the concept was originally planned for limited production, Audi ultimately pulled back, saying it didn’t have the resources to build the car.
Now it’s back. At this year’s Frankfurt Motor Show, Audi took the wraps off the Sport Quattro Concept (this time in a yellow-and-orange metallic paint scheme rather than th…