Built Around a Different Engine Than the STI
The FA20DIT's open-deck aluminum block handles moderate power increases well, but it has less boost headroom than the STI's semi-closed-deck EJ257. That matters for Subaru WRX engine upgrades, since engine hardware built for the EJ family won't bolt on or tune correctly here.
A COBB Accessport is the starting point for most builds, letting you flash a tune that matches whatever hardware you add next. Pair it with a quality air oil separator to keep oil out of the intake tract as boost climbs.
Choose the Right Path for Your Build
Chasing more airflow? A Subaru WRX engine turbo upgrade from Garrett steps past the factory twin-scroll unit's ceiling, though it needs supporting fuel system work to run safely.
Not ready for a full turbo swap? Smaller Subaru WRX engine upgrades, like DeatschWerks fuel injectors and a matching fuel pump, raise your safe power ceiling on the stock turbo. IAG Performance parts round out the fuel side of the build.
Support Your Long-Term Build
Serious builds need cooling to match. Mishimoto cooling upgrades keep intake and oil temperatures in check once you're making more power than stock. Torque Solution mounts cut drivetrain movement that gets worse as torque climbs.
Every listing on JDMuscle's Subaru WRX engine upgrades page includes verified fitment details, so a turbo, injector, or mount matches your specific FA20DIT build before you order. Turbosmart wastegates and blow off valves round out the boost control side once you're running more than stock boost.
