Porsche's return to the Detroit Show after a four year-absence is marked with the introduction of a new racing concept based on the company's 918 Spyder from last year's Geneva Salon. The 918 RSR is a two-seat mid-engined coupe, and according to Porsche, it demonstrates what happens when the technology fitted in the 911 GT3 R Hybrid race car and the design of the 918 Spyder concept are combined together. Read more »