The last Head 2 Head we shared with you compared the Porsche Macan Turbo to the Mercedes-Benz GLA45 AMG. While fun and interesting, it didn't pack the exotic excitement of this latest episode. Today's hypercar battle is one for the ages: the McLaren P1 versus the Porsche 918 Spyder. Both cars have carbon fiber tubs and body panels. Both have small displacement, high revving V-8s packed between their passenger compartments and rear axles. Both use twin-clutch transmissions, carbon ceramic brakes, and active aerodynamics. Both have roughly 900 hp. Both are plug-in hybrids. Both will be driven by Randy Pobst around Mazda Raceway Laguna Seca. Which hypercar was faster? Watch the video and find out for yourself.