The fourth generation of the Subaru Legacy was introduced in 2003 and saw a complete redesign of the Legacy on an all-new platform. Development began by the beginning of 1999, with styling freeze in early 2001 and engineering sign-off in 2003.
Japanese model
On May 23, 2003, Fuji Heavy Industries continued to offer the "Blitzen" model in Japan only, and debuted the fourth generation Legacy B4 sedan for the Japanese domestic market with the slogan "Blood type: B4" and advertisements featuring a remixed version of "Gymnopédie No. 1" by Erik Satie. The station wagon debuted with the slogan Grand Touring Speciality and the song in the advertisements was "Finding Beauty" composed by Scottish composer Craig Armstrong from his second independent album As If to Nothing. The Legacy B4 sedan and station wagon was voted the 2003–2004 Japan Car of the Year, Subaru's first win for the award after fighting off stiff competition from Toyota Prius and Mazda RX-8. In 2005 Bruce Willis returned as a spokesman for the second time after the first generation in 1991 to 1993 with tagline I feel LEGACY. Blitzen was a special package above the standard Legacy vehicles, and all Blitzen models were identified with the "B4" branding.
Starting with this generation, Subaru installed an electroluminescent instrument cluster which lights up when the engine is started, regardless if the exterior lights are on.
For the home market, the Legacy B4 and Touring Wagon were offered in 2.0i, 2.0R, 2.0GT, 2.0GT , 3.0R, and 3.0R trim levels. The base model 2.0i has SOHC version of EJ20 engine producing 140 PS, and the 2.0R comes with 165 PS DOHC engine. The turbocharged EJ20 DOHC engine installed in the 2.0GT and 2.0GT producing 280 PS Due to advancements in turbocharger technology and tightening emission standards, the twin-turbo setup was replaced by a twin scroll turbo and AVCS. The 3.0R and 3.0R are powered by the new 250 PS 6-cylinder EZ30 engine.
To commemorate Subaru's 50 years of making automobiles and The First Japan Car of the Year Victory, the 50th Anniversary Legacy was released in January 2004. This special edition model was based on the Legacy 2.0R, and 2.0GT.
The Legacy Blitzen of December 2004 is the special edition based on the 2.0GT B4 and Touring Wagon. These high-performance sports models came with special colour bright red, sports suspension, 18-inch alloys, unique grille, and aero-style bumpers.
Based on the Legacy 2.0GT B4 and Touring Wagon, the WR-Limited 2004 was released in July 2004, and the 2.0GT-based WR-Limited 2005 was launched in August 2005. The WR-Limited models were painted in WR Blue Mica, and came with Gold alloy wheels, front under spoiler, special blue and black seats, and special emblems.
Also added to the Japanese line-up in August 2005 was the Legacy 2.0GT tuned by STI. This sports model has Bilstein suspension, 5-speed for 2005 or 6-speed manual for models after 2006, STI genome exhaust, Brembo brakes (4-piston front, 2-piston rear) and 18-inch alloy wheels by STI.
Facelift model (2006–08)
The Japanese Legacy received a cosmetic update in May 2006. Notable changes included new bumpers, headlights, front fenders, grille, and rear combination lamps. This facelift trickled down to export models in 2007.
Kazuyoshi Miura was used as a spokesman for the Hardtop, Touring Wagon and Outback and the commercial song were from Japanese rock band L'Arc-en-Ciel.
Although model grades remained largely unchanged, the number of option packages available for certain grades reduced. The base model 2.0i Touring Wagon could also be ordered as the Casual Selection model. Urban Selection models were added to the 2.0R, 2.0GT, and 2.0GT SI-Cruise. The 2.0R was also offered as B-Sports Limited version.
EyeSight (2008–09) On 2008-05-08, Subaru announced the EyeSight models for Japanese market. It consists of 2 CCD cameras with one on each side of the rear-view mirror, that use human-like stereoscopic vision to judge distances and generally keep tabs on the driver. The system included the ability to help the driver maintain distance on the highway, a lane departure warning system, a wake up call alerting the driver to a change in traffic signals, and pedestrian detection. SI-Cruise has been integrated into the EyeSight feature as a driver safety aid. EyeSight was a new brand name for a safety system Subaru had previously introduced in Japan only in the 1999 Subaru Lancaster (Outback) called Active Driving Assist (ADA)
EyeSight models were available for Touring Wagon 2.0GT and 3.0R, B4 3.0R, Outback 3.0R. All EyeSight models include Sportshift E-5AT transmission.