PistonHeads takes a Porsche 911 RSR GTE to Vallelunga, Italy, for a full-throttle test drive of Porsche’s Le Mans-winning race car. Unlike road-going 911s, this GTE is a purpose-built competition machine, with bespoke carbon-fiber bodywork, a mid-mounted 4.2‑liter flat-six producing 515 hp, a six-speed sequential gearbox, steel racing brakes, and slick...