Although it won't officially debut until the 2013 Frankfurt Auto Show,
Porsche is busy testing prototypes of its upcoming 918 Spyder. Our always-reliable spy photographers have just managed to snap pictures of a 918 test mule doing some hot laps around the
Nurburgring, and it looks delicious in greyscale Martini livery. Unlike the German sportscar builder's previous supercar, the Carrera GT, the 918 Spyder will be a plug-in hybrid.