The Porsche 911 Speedster Concept: open-top, pure and with over 500 hp Stuttgart. Porsche will be giving itself an excellent present for the 70th anniversary of its sports cars: the 911 Speedster Concept is a road-ready study of an open-top and particularly exciting sports car. It forges a link between the very first Porsche 356 ‘No. 1’ Roadster, which received its operating permit on June 8, 1948, and the Porsche cars of today. With its pure…