1973 was a landmark year for Porsche's 911 sports car. It was the last year for the small bumper 911 body style and marked the first year for the legendary RS model — the ultimate evolution of the platform. Stripped of everything unnecessary, the lightweight Carrera RS was designed to perform as well on the racetrack as it did on the street. Before the RS went into full production, nine prototypes were made, and the RS pictured here is the second. The car was originally a gift to the promising young race driver Helmuth Koinigg, before eventually making its way into a US collection. The car returned to Austria where it was first sold and is still in nearly original condition. With the RS being the car that would make the 911 one of the greatest racing platforms of all time, this is an important piece of Porsche's history.