The 2005 Subaru Impreza WRX STI (GDB generation) is a performance-oriented compact vehicle renowned for its rally-bred engineering and exhilarating driving dynamics. Featuring a potent 300 horsepower turbocharged 2.5-liter EJ257 Boxer engine, symmetrical all-wheel drive with a Driver Controlled Center Differential (DCCD), and a robust 6-speed manual transmission, the WRX STI offers exceptional traction and driver engagement. Its distinctive styling, advanced braking system, and performance-tuned suspension further solidify its reputation as a highly capable machine, appealing to enthusiasts who value precision handling and powerful acceleration.

This comprehensive factory service manual provides detailed information for the maintenance, repair, and troubleshooting of your 2005 Subaru Impreza WRX STI. It covers all major systems, including the engine (EJ257 variants), transmission, chassis, body, and electrical systems, offering in-depth procedures for everything from routine maintenance and fluid changes to complex component overhauls and diagnostic routines. With extensive technical specifications, wiring diagrams, and guidance on specialized tools, this manual is an essential resource for owners and technicians alike, ensuring the optimal performance and longevity of this iconic performance vehicle.