This is a Cool Video Demonstrating Subaru's Symmetrical All-Wheel Drive

Efficiency and Durability

Symmetrical All-Wheel Drive has the engine mounted in-line with the drivetrain, helping provide a seamless transfer of power to all four wheels.
Other AWD systems need additional drivetrain components to route the same power to the wheels, often using complex

http://www.subaru.com/engineering/all-wheel-drive.html