For the latest model year, the STI gets an interior revamp, new Recaro seats, upgraded brakes, and a limited-edition "Type RA" variant co commemorate Prodrive's record lap time at the Nurburgring.
At first glance, the STI is visually similar to the WRX, but a closer look reveals that the STI subtly advertises its heightened capabilities with aggressive touches like deeper front air intakes, narrowed "falcon eye" headlights, burlier fenders and an oversized rear wing.
Power comes from a turbocharged 2.5-liter boxer four-cylinder that produces 305 horsepower at 6,000 rpm and 290 lb-ft of torque at 4,000 rpm. STI buyers will need to know how to drive stick - a slick-shifting six-speed manual is the only transmission available. It helps the sedan to accelerate from zero-to-60 mph in a claimed (and likely conservative) 5.1 seconds.
Brembo brakes bring the action to a halt, including four-piston calipers with 13.4-inch rotors up front, and two-piston calipers clamping 12.8-inch rotors at the rear.
Setting the WRX STI further apart from the standard WRX is its Multi-Mode Driver Controlled Center Differential mated to Subaru's existing all-wheel-drive system. A planetary-type center differential delivers up a nominal 41/59 torque split (front/rear), while a mechanical limited slip center differential helps apportion that power fore and aft in one of three automatic modes. A manual mode lets drivers pick one of six pre-selected center differential locking levels for various driving situations.
Another element of the WRX STI's performance arsenal is Active Torque Vectoring, which uses the car's stability and traction control systems to apply brake pressure to the inside front wheels for more neutral cornering. Notably, the stability control gives drivers the choice of three settings - normal, traction control only and off.
Further choices are offered up by Subaru's Intelligent Drive - or SI-Drive - powertrain management system, which features Intelligent, Sport and Sport Sharp modes accessed by a center console-mounted dial. Intelligent delivers a more relaxed feel, while Sport and Sport Sharp dial up responses for extra driving fun.
Unlike the standard WRX, as well as the Impreza economy sedan with which it shares a platform, the STI uses an inverted strut front suspension to improve cornering. Aluminum lower L-arms up front reduce unsprung weight. This stiffened setup delivers a ride that's firm yet livable for those who regularly traverse maintenance-neglected roads. The upside, of course, is relatively little body roll and impressive agility in turns.
The Inside Story
Like the WRX, the STI's interior is based heavily on that of the Impreza. That means a simple, no-nonsense design that trades expressive flourishes for intuitive ergonomics. Sporty, STI-specific elements include a flat-bottom steering wheel, (optional) combination alcantara/two-tone leather sports seats, imitation carbon fiber trim, and a red-face shifter knob. Recaro front sport bucket seats are optional.
Informative instrumentation is one of the STI's strong points. A special STI Design electroluminescent gauge panel uses a 3.5-inch LCD screen to display certain functions, including the selected gear, and a 6.2-inch screen mounted on the dashboard provides info on boost pressure, the traction control system, audio settings and Bluetooth connectivity.
The STI comes with a new 6.2-inch touch screen that runs the latest generation of Subaru's StarLink infotainment system. Through a user's Bluetooth-connected smartphone, Starlink provides access to Aha radio, which offers tens of thousands of stations of Web-based content like Slacker, MOG and Rhapsody.
Although undeniably not as practical as its five-door hatchback predecessor, the STI does boasts 12 cubic feet of trunk space and decent rear seat room. The rear seats fold down 60/40 in order to free up extra trunk space.
Trim Level Breakdown
The STI is offered in base model and Limited trims.
The base model comes standard with full power accessories, dual-zone automatic climate control, heated front seats, a six-speaker AM/CD/HD radio/SiriusXM stereo with USB and AUX inputs, a rearview camera, Bluetooth connectivity, cruise control, heated exterior mirrors, automatic headlights, auto up/down front windows, windshield wiper de-icer, and 18-inch alloy wheels.
To those features, the Limited adds or substitutes leather upholstery, power-adjustable driver's seat, harmon/karmon audio, a moonroof, and 18-inch BBS forged alloy wheels.
Buyers can spruce up the STI by selecting an option package that bundles navigation, a 7.0-inch touch screen, an upgraded harman/kardon sound system as well as keyless entry and start. Additionally, the STI's huge wing can be replaced by a more discreet trunk-mounted spoiler at no extra cost.
For this model year only, Subaru is offering a limited run of "Type RA" models with a small bump in power, unique appearance features and a re-tuned suspension to commemorate Prodrive's record-setting Nurburging lap in a race-prepped STI.
Only 500 units will be sold in the U.S., all in World Rally Blue, Crystal Black and Crystal White.
All STI models are fitted as standard with dual front, front side and full-length side curtain airbags in addition to a driver's knee airbag and traction and stability control systems.
Subarus appeal to two very different groups: families seeking safe and reliable transportation, and younger buyers seeking fast, fun, all-wheel drive performance vehicles. The Impreza WRX STI is aimed at the second group. The Mitsubishi Lancer Evolution X, its biggest competitor, has been phased out, but buyers can also consider the Volkswagen Golf R and the Ford Focus RS.