More ACT parts:All ACT parts WRX 2022+ WRX 2015-2021 WRX 2008-2014 WRX 2002-2007 STI 2015-2021 STI 2008-2014 BRZ 2013-2020 Drivetrain Clutch Drivetrain Clutch Discs / Replacement Parts Drivetrain Flywheels
Shop ACT parts for the 2004-2007 Subaru Impreza WRX STI. The GD-chassis US STI runs the EJ257 2.5-litre turbocharged flat-four with a 6-speed manual and Driver Controlled Center Differential - there was no automatic - every ACT product in this collection is fitment-tagged for that exact vehicle, so check the product fitment notes against your car before ordering.
Everything in this collection - each product listed here is a ACT part fitment-tagged for the 2004-2007 Subaru Impreza WRX STI. Fitment can still vary with trim level and factory options, so confirm the fitment notes on the product page before ordering.
This collection is tagged for the GD-chassis STI only, which is a separate fitment from the same-years WRX - different engine build, brakes, drivetrain and suspension. Match parts to the STI listing, not the WRX one.
The full ACT collection is linked at the top of this page. From there you can also shop ACT by vehicle or by part type - WRX 2022+, WRX 2015-2021, WRX 2008-2014, WRX 2002-2007, STI 2015-2021, STI 2008-2014 and more are all linked above.