As Subaru had intended to homologate the sedan chassis for rallying, the decision to increase the width of the sedan—which placed it into the higher taxed number "3" division—brought added stability.

In Subaru's home market of Japan, the Impreza range started with the 1.5i—powered by the 1.5-liter EJ15 SOHC engine and paired with a manual transmission or optional automatic.

After mixed reaction to the round headlight design, in 2001 Subaru enlisted the help of Peter Stevens of Prodrive, who updated the car's fascia in 2002 (2003 in the US for the 2004 model year), with more rectangular headlamps.

2005 STis received the long-awaited DCCD control available in other markets, as well as a slight wheelbase increase to match the Japanese-spec WRX STi Spec-C and has 280 PS (210 kW; 280 hp).

Along with the rest of the Impreza line, the grille and body of the WRX STi was lightly updated by Peter Stevens to give it a more angular look when seen from the side.

Subaru unveiled this model at the Detroit International Auto Show, only 1 month after Mitsubishi announced the arrival of the 271 horsepower Lancer Evolution 8, which out-performed the 2.0L WRX.

For the STI, changes include a different turbocharger VF43 equipped with a slightly larger wastegate port to prevent boost creep (VF43, as opposed to VF39 in the older version) and revised gearing on the 6-speed manual transmission.

Apparently, Petter Solberg, Subaru driver and winner of Rally GB at that time, reckons that of all the roadgoing Imprezas he's driven, the S202 feels most like his WRC car.

The exterior featured an adjustable carbon-fiber GT-style wing at the back (of which only 400 were produced) and a manually operated roof vent – rally car style.

[citation needed] Suspension can be described as 'stiff' with torsional rigidity enhanced by the inclusion of laterally mounted items described as "performance dampers" bearing both the STi logo and Yamaha.

The addition of a carbon fiber front-lip spoiler and a rear diffuser on an already low suspension setup plus the use of low-profile Pirelli P Zero (Corsa) tires implies the S204 is intended mostly for sealed road use.

The high side bolsters provide significant support to the driver during maneuvers that induce lateral forces and are considered to be an integral feature to the cornering performance of this vehicle.

Individually numbered badges for each car are located within the engine bay and repeated as a small plaque situated at the base of the gear lever.

[15] Unlike other S204s sent to other nations (for example 30 units for Singapore) these five cars do not display either the in-cabin or in-engine bay badging that uniquely identifies each of the reported 600 vehicles manufactured.

The Australian market models received an engine upgrade to 168 kW (228 PS; 225 hp) and 300 N⋅m (221 lb⋅ft) of torque via a compression ratio increase to 9.0:1 and the addition of variable valve timing on the intake camshafts.

The 4 gear electronic automatic transmission (4EAT) WRXs have a Variable Torque Distribution AWD system instead of the conventional viscous coupling center differential.

VTD employs an electronically controlled hydraulic transfer clutch and a planetary gear center differential to distribute power in a 45:55 split between the front and rear axles under normal circumstances.

The VTD system uses multiple sensors to measure front and rear driveshaft speeds, throttle position and gear selection.

There is also a valve that prevents "drop-clutch" starts in an effort to reduce the number of shattered gear boxes from abusive AWD launching.

[16] The steering rack is the standard STi's 15.2:1 instead of the Spec C's 13:1 The WRX received an updated interior, body color rocker panels, black painted headlamp bezels, and wheels that were previously seen on the base US-spec Legacy and a single-port exhaust.

For 2006 the Subaru Impreza WRX received a complete front-end redesign, restyled headlights with smoke-tinted lenses, a three-section mesh-type grill, and distinguished new tail lamp clusters.

Due to Subaru's decision to reduce costs by cutting the amount of aluminum used, the US-spec STI no longer receives the J-spec Spec C control arms.

The WRX STI Limited was introduced with fog lights, leather interior, lip trunk spoiler, and optional moonroof.

300 vehicles limited to the UK market were sold with Blue Mica exterior paint, 17" gold alloy wheels with 215/45 tires, Subaru World Rally Team branded front bucket seats, a 5-speed manual transmission and the Prodrive Performance Package (PPP) all as standard equipment.

As standard, it has projector-style fog lights, Smartnav with touch screen operation, Vehicle Tracker, and safe speed system.

Echoing the RB5, a limited edition of 320 2007MY STI cars in Obsidian Black Pearl were released "in memory of Richard Burns", the 2001 WRC World Champion, who died in 2005 due to a brain tumor.

The interior received extra acoustic insulation over the Subaru, with particular attention paid to the firewall, carpeting, roof, and rear window seals.

Saab offered a two-tone seat design based on the earlier (second generation) Impreza wagon, as well as the instrument cluster from that car.

The rear suspension arms are aluminum, with further reduction of unsprung weight achieved by using plastic in place of heavier components, bushings unique to the Saab, and recalibrated dampers.

When ordered on with the "Linear" trim, the Premium package also included the in-dash six-CD changer, front fog lamps, vinyl door cards, and a leather-wrapped steering wheel and shift knob.