IAG Performance

IAG Performance – Air Oil Separators & Built Engines for Serious Subaru Enthusiasts

If you've ever dealt with oil consumption, fouled spark plugs, or pre-detonation caused by oil vapor in your intake, you know how frustrating EJ and FA engine oiling issues can be. IAG Performance has developed purpose-built solutions to address these common Subaru problems—from daily-driven WRX to full-race STI builds. At JDMuscle, we carry the full IAG lineup to keep your engine healthy and performing at its best.

IAG Air Oil Separator (AOS) – Solve Your PCV Problems for Good

The EJ and FA engines are known for allowing oil vapor to pass through the PCV system and into the intake manifold—leading to carbon buildup, reduced octane rating, and in severe cases, engine knock. The IAG AOS eliminates this issue with a 1-liter cast aluminum swirl pot canister that separates oil from PCV gasses before they re-enter your intake.

Unlike basic catch cans that require regular draining, the IAG AOS is a maintenance-free design. Separated oil collects on the canister walls and slowly drains back into the crankcase. An integrated heating element keeps the collected oil free of sludge and moisture, so there's no risk of contamination. It works seamlessly with your factory ECU calibration and supports all fuel types including E85. For turbocharged Subarus running higher boost or aggressive tunes, an AOS is one of the smartest investments you can make to prolong engine life.

Available for 2002-2014 WRX, 2004-2021 STI, 2015-2021 WRX (FA20), 2022-2025 WRX (FA24), Forester XT, and Legacy GT.

IAG Short Blocks & Long Blocks – Drop-In Crate Engines Built for Power

The IAG 550 package is designed for street performance builds supporting up to 550 BHP—ideal for bolt-on turbo upgrades and aggressive daily drivers. The IAG 750 closed deck long block handles up to 750 BHP, perfect for big turbo setups and weekend track builds. For dedicated race applications, the IAG 950 package supports up to 950 BHP with fully closed deck construction and race-spec heads. Extreme builds can step up to the IAG/Crest CNC Stage X billet aluminum short block, rated for 1150+ BHP.

All long block packages are complete valve cover to valve cover, making them true drop-in solutions for WRX, STI, Forester XT, and Legacy GT.

Trusted by thousands of enthusiasts, JDMuscle offers free shipping on orders over $199, a price match guarantee, flexible pay-over-time options, and our rewards program.Browse our full selection of IAG Performance products and give your Subaru the protection and power it deserves.