Here's the portion of one of Mazda's press releases as it pertains to the AWD:
All-New Active Torque Split All-Wheel Drive System
The Mazda6 MPS is equipped with Mazda's new active torque split, all-wheel drive system. Based on the road-proven system of the Mazda6 available in some global markets, but featuring more aggressive transfer of torque to the rear axle on all road surfaces in accordance with driving conditions, the new all-wheel-drive system achieves a fine balance between sporty control over the car that makes it particularly fun to drive and handling stability on snowy or wet surfaces or under other challenging road conditions. Power and torque are faithfully and thoroughly transferred to the road surface for maximum efficiency and performance.
The system uses real-time input data on steering angle, yaw rate, lateral G force and engine status to determine road surface and driving conditions. The active torque coupling mounted in front of the rear differential is electronically controlled accordingly, adjusting front/rear wheel torque distribution between 100:0 and 50:50 to deliver optimum drive power to each wheel. The result is powerful acceleration and positive handling regardless of constantly changing road conditions, as well as the ability to fully balance the car in a turn by deft use of the accelerator pedal.
The Mazda6 MPS's onboard computer automatically determines driving and road conditions so the driver can relax and enjoy the pleasure of the drive. Three different modes of front/rear torque distribution are selected by the system: Normal, Sports, and Snow, (for slippery surfaces). The Power Take Off (PTO) system that that aggressively distributes torque to the rear axle is fitted with its own water-cooled cooling system.
A new rear differential with greater torque capacity is employed by the system to deliver a high level of reliability. Increased torsional rigidity of the propeller shaft and rear differential mount improves the response of torque transfer to the rear wheels and delivers a more rigid feel to the ride under acceleration. And a limited slip differential is used in the rear differential optimizes transfer of torque to the left and right rear wheels, realizing solid traction and linear vehicle control that delivers a stable feeling ride when cornering.