More Subaru STI 2004-2007 parts:
All Subaru STI 2004-2007 parts | Brakes | Drivetrain | Tuning | Exhaust | Exterior | Intake | Interior | Suspension | Turbo | Cooling | Wheels | Fuel | Fluids | Wheel Accessories | WheelSpacers | Electronics
Shop engine parts for the Subaru WRX STI 2004–2007 (GD chassis). The US-spec GD STI runs the EJ257 2.5L turbocharged flat-four — not the 2.0L EJ207 sold in other markets — with hypereutectic cast pistons from the factory. You will find internals, gaskets, engine mounts, pulleys, hardware here — every part in this collection is fitment-tagged for the 2004–2007 WRX STI, so check your year and engine against the product fitment notes before ordering.
What engine parts fit my Subaru WRX STI 2004–2007 (GD chassis)?
Every engine part in this collection is fitment-tagged for the GD-chassis WRX STI (2004–2007) and its US-spec EJ257. The engine is the same EJ257 across the run, but 2007 brought redesigned cylinder heads for improved cooling and a switch to top-feed injectors, so some parts split by year — confirm your model year on the product page before ordering.
When should I consider forged pistons for an EJ257?
The stock EJ257 uses hypereutectic cast pistons, and owner communities commonly discuss the pistons — the ringlands in particular — as the first stock component likely to fail as power is turned up, with stock ringlands commonly discussed as cracking above about 350 whp. If your build goes beyond mild bolt-ons, forged pistons are the usual EJ257-specific upgrade to plan for, sized to your power goal and tune.
Where can I find other parts for my Subaru STI 2004-2007?
Start with the full Subaru STI 2004-2007 collection linked at the top of this page, or jump straight to a category — Brakes, Drivetrain, Tuning, Exhaust, Exterior, Intake and more are all linked above, and every one of them is scoped to the Subaru STI 2004-2007 only.