Upon its 2003 introduction, the current Forester earned the highest possible ratings ("Good") in side-impact and 40-mph offset frontal crash tests conducted by the Insurance Institute for Highway Safety (IIHS), which dubbed the Subaru the "best small SUV" it had tested. Front-seat passengers are protected by dual-stage front airbags and seat-mounted side-impact airbags, as well as seatbelt pre-tensioners and force limiters. All five seating positions get headrests and three-point seatbelts; outboard belts are height-adjustable. A four-channel/four-sensor anti-lock braking system is standard on all Foresters; the base 2.5X model gets front-disc/rear-drum brakes, all others get four-wheel discs. Stability control is not offered.
The Forester's base engine, standard in 2.5X and 2.5X Premium Package, is a SOHC 2.5-liter horizontally opposed four with four valves per cylinder. Revised for 2006, the boxer-configuration engine now employs what Subaru has dubbed the i-Active Valve Lift System, which gives one of each cylinder's two intake valves a "high" and a "low" position. At low revs, the two intake valves open at different positions, causing a swirl of fuel and air that aids combustion and boosts torque. At high revs, both valves assume the "high" position, letting in more air for higher horsepower. Horsepower is up from 165 to 173, and peak torque is unchanged at 166 lb-ft. The Forester 2.5XT Limited features a turbocharged and intercooled version of the 2.5-liter flat-four engine. Also revised for 2006, the turbocharged engine's enhanced horsepower (230, up from 210; torque is unchanged at 235 lb-ft) arrives courtesy of a higher compression ratio (8.4:1, up from 8.2:1) and redesigned intake and exhaust systems. The turbo engine bests the output from all four-cylinders in the segment.A five-speed manual transmission, equipped with a clever Hill Holder device to prevent rollback during uphill starts, is standard with both engines. A new four-speed automatic is optional. First introduced on the 2005 Legacy, the auto transmission adjusts shift points based on inputs and load to optimize performance.
All-wheel drive, as with every Subaru model, is standard on the Forester, but it's worth noting that there are two versions of the system here. Foresters with the manual gearbox feature all-wheel drive with a viscous-coupled locking center differential that splits the engine's power 50/50 percent between the front and rear wheels. Slippage at the front or rear prompts the system to shunt power to the opposite axle to maintain traction. Foresters equipped with the automatic gearbox feature a more sophisticated electronically managed, continuously variable transfer clutch that can deliver power to the individual wheel or wheels that are best able to make use of it, and even performs such tricks as apportioning more torque to the rear wheels during acceleration, to take advantage of the rearward weight shift. A viscous limited-slip rear differential, which redirects power across the rear axle when slippage is detected, is standard with either gearbox on 2.5X Premium Package and 2.5XT Limited models.
On paper, the normally aspirated engine's eight-horsepower bump for 2006 hardly seems noteworthy. On the road, however, the engine feels altogether new: A torque curve that peaks quicker and stays flatter gives the Forester a newfound spiritedness, and the increased power at higher revs greatly eases tasks like highway passing. As before, turbo lag on the XT Limited is noticeable but not noisome, and the four-wheel-driven thrust is decidedly un-SUV-like. Quite impressive, the force-fed Forester will leap to 60 mph in a tick under six seconds. The Forester's minimum ground clearance increases from 7.5 to 8.1 inches for 2006 (7.9 inches for the turbocharged model), but thanks to recalibrated front and rear spring rates and damper valving, the additional height has no discernable effect on the Forester's oft-praised road manners. Overall, the driving experience is far more carlike than that of other small SUVs, which can feel cumbersome and top-heavy during hard cornering, braking, and acceleration.