Subaru was seen as one of the world's top rally racing teams, but is no longer active at a factory level in the WRC.

[5] STi president Ryuichiro Kuze partnered with British firm Prodrive in 1989 to develop a rally car using the Subaru Legacy chassis.

[6] The resulting performance model was the Legacy RS, which produced 220 PS (160 kW; 220 hp) mated to a five speed gearbox and weighing just over 2,600 pounds;[citation needed] it was manufactured by Subaru to homologate the type for FIA Group A racing.

[citation needed] One of the first activities that STi carried out was setting the world record for 100,000 km (62,000 mi) endurance driving using a fleet of three modified Subaru Legacy RS sedans, averaging 223.345 km/h (138.780 mph) over most of January 1989.

[8] The founder of STi, Noriyuki Koseki, coordinated the FIA World Land Endurance Record attempt and drove one of the cars.

[9] The Legacy RS used a 2.0-liter EJ20 turbo engine; STi modified the record-setting cars by tuning the suspension and improving the aerodynamics.

[10] Low-volume Type RA production continued after that initial model, and in 1992 the Legacy Touring Wagon STi was marketed with similar modifications.

[10] Subaru first campaigned the Prodrive-developed Legacy RS in the 1990 WRC season, finishing fourth in the constructor's standings that year.

[13] The Impreza 555 featured a 2.0-litre intercooled turbocharged engine with 250 horsepower, upgraded suspension that could take on more aggressive potholes and jumps, as well as a short shifting transmission which made switching gears more accessible and quicker.

[34] Subaru were unable to repeat their title in 2017, with the car forced to retire due to a fire in the engine compartment; at the time, the team were in second place within the class.

[41] STI also participates in the GT300 class of the Super GT series, campaigning the Legacy B4 GT300 starting in 2009, then switching to the BRZ GT300 from 2012 onward.

While the WRX was first released for the North American market in 2001 for the 2002 model year, the limited production Impreza WRX STI sedan with 300 hp and 310 foot pounds of torque did not hit the market until 2004, and the USDM version having a number of changes when compared to the JDM - most notably the 2.5L EJ257 as opposed to the 2.0L EJ207 found in the JDM Spec model.

[citation needed] These are rare and sought after by Subaru enthusiasts, and marketed as 'Tuned by STi' They were only released new in Japan (JDM) and New Zealand (NZDM) this has been throughout the 2005-2007 Legacys.

The higher performance 'STI Legacys' are produced in limited numbers for the Japanese Market only and are known as S-Line, (see more below) similar to what has been carried out in the Impreza model range.

[citation needed] Drawings of a BRZ STI exist online and concepts have been shown at auto shows, but Subaru has yet to release an official statement.

[citation needed] The highest-performance automobiles sold by Subaru are limited-production models tuned by STI and designated as the "S-line".