2015 Subaru WRX STI

Redesigned for the latest model year, the Subaru WRX STI continues to be a rally-bred, enthusiast-focused sedan that delivers even more performance than the standard WRX. However, increased levels of comfort and refinement mean that it's now as comfortable doing the daily commute as it is blitzing the backroads.

Notably, unlike the last-generation model, the current WRX STI is not offered as a hatchback.

Overview
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 13.0-inch rotors up front, and two-piston calipers clamping 12.4-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.

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 4.3-inch LCD screen mounted on the dashboard provides info on boost pressure, the traction control system, audio settings and Bluetooth connectivity.

Overly fussy and generally confusing to use, the optional navigation system is one of the worst units in any modern vehicle. At least it offers good functionality through Subaru's Starlink connectivity system, which provides smartphone-based access to Aha radio, Facebook and Twitter.

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. A special Launch Edition, detailed below, will also briefly be available.

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, 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.

A navigation system with a 6.1-inch LCD touchscreen is optional on all STIs, while the base model can be spec'd with the Limited's harmon/kardon stereo.

Launch Edition
To celebrate the debut of the new STI, Subaru is offering a special Launch Edition model. Limited to a run of 1,000 units, it builds off the base model with WR Blue paint, gold BBS alloy wheels, exclusive blue interior trim, an STI short-throw shifter and remote start.

Occupant Safety
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.

Key Competitors
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 Sedan is aimed at the second group, finding its biggest competition in the rival Mitsubishi Lancer Evolution X. Some may also consider the Mazda Mazdaspeed 3 and the Ford Focus ST.