One of the longest-running models of sports car in existence, the latest Porsche 911, codenamed the 991, features a lower roof, more bulbous headlights and sharper tail lights. The engines have received several tweaks, too. The standard Carrera's 3.6-litre, six-cylinder engine is replaced by a smaller 3.4-litre that's more efficient but produces more power - 345bhp. The 3.8-litre found in the Carrera S now produces 394bhp. Performance, when fitted with the PDK twin-clutch gearbox in particular, is very impressive. The standard Carrera sprints from 0-62mph in 4.6 seconds, while the Carrera S does it in just 4.3 seconds. The interior has received a major makeover, inspired by the Panamera but with fewer switches. Most owners will opt for the PDK gearbox but Porsche also offer a seven-speed manual option - the first of its kind in a production car.