Adopting a mid-engine, RWD layout, the new 911 RSR uses a 4.0 L naturally aspirated flat-6 engine developed from the 991.1 GT3 RS/991.2 GT3 and upgraded to make 503 hp (375 kW) and 340 ft·lb (461 N·m). With a weight of 2740 lb (1243 kg), the 911 RSR has a power-to-weig...