We drove the Porsche 718 Cayman GT4 RS, Ford patented a hydrogen combustion engine, and Jay Leno drove an unrestored 1931 Auburn 8-98 A. It’s the Week in Reverse, right here at Motor Authority.Porsche put us behind the wheel of the 718 Cayman GT4 RS on the Streets of Willow circuit in California, and we learned it’s a love letter to mid-engine…