At the New York Auto Show, a Subaru spokesman confirmed that the Impreza WRC will be based on the hatch platform, due to its lower polar moment of inertia.

The latest US model of the STI has 305 bhp (227 kW; 309 PS) and 290 ft·lbf (390 N·m). of torque and range in price from $35,640 to $39,440, depending on the options included. The 2008 Impreza STI has the model code GR, reflecting the different “wide body” 5-door Hatchback compared to the GH standard body 5-door Hatchback used for the 2008 Impreza WRX and non-turbo models. The new “wide body 5-door” chassis is 70.7 in (1796 mm) wide compared to 68.5 in (1740 mm) for the regular WRX 5-door chassis. Kerb weight varies from 1,505 kg (3,318 lb) to 1,540 kg (3,395 lb) depending on the options.

In 2008, a Subaru WRX STI spec C was in the works for production. It had been spotted lapping the Nurburgring. It is expected to shed 70 kg (154 lb) in weight, have minor engine tweaks, have an updated aero kit, and bigger brakes.

A possible precursor to the WRX STI spec C had surfaced at the MotorSport Japan 2008 auto show, named the Subaru Takumi concept. The only visual cues to differentiate this car from the regular STI are a blacked-out rear spoiler, front lip spoiler, and 12-spoke wheels that are strikingly similar to the ones featured on the spec C test mule spotted around the Nurburgring. The upgraded parts included on the car are drivetrain and suspension modifications. There is no word on performance figures or power output. It was later confirmed by Autoblog that the Takumi concept was in fact just an unveiling of the 20th Anniversary Edition WRX STI and not the spec C. All 300 examples will be exclusive to the Japanese market.