As with all Subarus, power gets to the ground through all four wheels, all the time. The STi gets the most performance-oriented version of Subaru's symmetrical all-wheel-drive system with the DCCD. This system provides automatic fore-and-aft torque distribution, with a static 35 percent front/65 percent rear distribution, or a driver-variable torque split as in pro rally cars. Programming for the DCCD has been revised this year to improve cornering ability in automatic mode. Additionally, both the front and rear differentials are limited-slip units for optimum side-to-side power distribution; the front differential is now a helical type for improved grip in tight corners.
In high-performance driving situations, it works very well. Accelerating from 0 to 60 takes less than 5 seconds. The STi is set up for hard cornering, and the suspension tuning and extraquick steering mean that at speed, 100 percent of the driver's attention must be paid to driving. Yet it's docile in stop-and-go traffic and completely capable of living in the everyday world if you can stand the extra cabin noise.
Like all Subarus, the Impreza WRX STi uses the ring-shaped reinforcement unibody construction to surround passengers with a strong safety structure. The hydroformed front subframe is designed for occupant protection, and dual front and front-seat-mounted side air bags are standard equipment. A high-performance car must stop as well as it accelerates, and the STi scores very well here. The Brembo brakes have 12.7-inch vented rotors and four-piston calipers at the front, as well as 12.3-inch vented rear rotors with two-piston calipers at the rear. Electronic brake-force distribution and the Super Sport antilock system, which uses a lateral-G sensor and controls each rear brake separately, provide fast, consistent stopping power. Traction control is done the old-fashioned way, with the right foot and steering wheel. Driver-adjustable headlight aiming is an interesting piece of standard equipment, letting the driver aim the lights higher for improved distance coverage or lower for normal traffic situations.