Following the introduction of the first generation Impreza in Nov. 1992 and the following year's debut of the Group A rally car into the WRC, an 'STi version' was made commercially available in Jan. 1994 as a homologation model under FIA regulations.

555 (the cigarette brand that was the premier sponsor of the Subaru World Rally Team and became synonymous with the Impreza WRC livery) WRX Type RA STi Version 2 V-limited were produced.

It was essentially a 2-door version of the WRX Type RA STi meaning it had DCCD, minimal sound insulation, close-gear ratios and hardened gearbox.

These have the same motor, gearbox and R180 diff as the Version III WRX STI Type R, including DCCD, aluminium bonnet and front guards, no sound deadening and thinner glass.

The 22B, which carries an additional 20 N M of torque, has been timed at 12.5 seconds, however AWD cars can be difficult to launch, due to potentially bogging down if engine speed is too low, or the clutch is not correctly taken up.

To counter the grey imports of high-performance Japanese variants, Subaru UK commissioned Prodrive to produce an 'official' limited edition of 1,000 two-door cars in Sonic Blue.

Options were available from Subaru consisting of 4 piston front brake calipers, electric Recaro seats, 18" OZ alloys and a P1(Prodrive) stamped backbox.

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

Subaru unveiled this model in 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.

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.

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 fibre front-lip spoiler and a rear diffuser on an already low suspension setup plus the use of low-profile Pirelli P Zero (Corsa) tyres 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.

[6] 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.

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).

The steering rack is the standard STi's 15.2:1 instead of the Spec C's 13:1 As with the Japanese-spec C models, US-spec STis received additional rear fender flaring in order to allow an increase in wheel size.

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.

It is similar to the Japanese-spec A-Line except it had a regular WRX spoiler on the boot, silver wheels (not Gold) and no rear roof vane.

Echoing the RB5 a limited edition of 320 2007MY 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.

Like other 2008 Impreza models, the 2008 STI benefits from a lower polar moment of inertia due to smaller overhangs, and also features a double wishbone rear suspension.

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.

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.[11] All 300 examples will be exclusive to the Japanese market.

The ball bearing on the turbine axle had been modified to reduce friction, the ECU had been retuned for better response, and an intercooler water spray was fitted to prevent rise in the air temperature.

The new WRX STI Sedan is built as "wide body" with flared fenders, front skirts, and rear valance, while the Hatchback model also comes with similar treatments.

The 2011 model year STI has stiffer springs, bigger anti roll bars, and new pillow ball bushings on the front lower arms, as well as wider standard tires .

The Cosworth Impreza STI CS400 can be distinguished from the regular STI from its upper mesh grille with piano black finish on the top frame, modified front bumper with "Cosworth" emblem on the lower mesh grille, and lip spoiler, 18 inch Pro-Race alloy wheels in Antrachite Gray, and trunk waist spoiler.

[21] The special edition variant also came with black STI embossed livery above the rocker panels on the driver and passenger side as well as orange stitching embroidered along the interior.

Subaru only manufactured 300 of these S206's, stickered at approximately 8,356,000 Japanese Yen (JPY) or 76,000$ (USD) brand new, making the S206 variant a rare, hard to find version of the STI.

Sheridan and RJ were involved in a collision around turn 453 In 2005, a 2004 STi took first place in the STU class of the Tire Rack SCCA Solo Nationals.

[27] In 2006, Deeble-Bellchambers Racing UK campaigned a Subaru factory supported WRX STI Spec C in the 24 Hour Nürburgring's SP 6 class.