Here's an interesting comparison test between the rear-wheel-drive 2012 Porsche 911 Carrera and its all-wheel-drive sibling, the Carrera 4S. Both, the 991 Porsche 911 Carrera and the Carrera 4S are powered by the same 3.4-liter flat 6-cylinder engine that develops 350 hp (257 kW). However, due to the obvious drivetrain and weight difference, the Porsche 911 Carrera 4S needs 4.5 seconds to get to 62 mph (100 km/h), while the Carrera needs just 4.4 seconds to reach the same speed.