The best parts for a 2002-2005 Subaru WRX are the ones that wake up the original US-market turbo WRX: a quality cat-back exhaust for sound and flow, a short shifter and drivetrain bushings to tighten the vague stock shifter, and a proper suspension setup to sharpen the GD chassis. Start with simple bolt-ons, then add a tune and supporting mods once you go beyond basic intake and exhaust work.

These early GD-chassis WRXs — the 2002-2003 "bugeye" and the 2004-2005 "blobeye" — are now 20+ years old, so pair performance parts with maintenance: worn bushings, tired struts, and aging gaskets cost more performance than most bolt-ons add. The good news is the aftermarket never left this platform, and most GD-chassis suspension and drivetrain parts interchange across all 2002-2007 WRX and STI models, keeping prices competitive and options deep.

Popular brands for this generation include Invidia for exhausts like the N1 Racing cat-back built specifically for 02-07 WRX and 04-07 STI, GrimmSpeed for drivetrain and cooling upgrades, and BC Racing coilovers for adjustable street and track suspension. Builders also favor the Borla unequal-length header for the classic boxer rumble. If you own the later GD years, browse the 2006-2007 WRX or 2004-2007 STI collections, and read our top 3 aftermarket parts for the WRX series for upgrade inspiration.

Will 2004-2007 WRX or STI parts fit my 2002-2005 WRX?

Many will. The 2002-2007 WRX and 2004-2007 STI share the GD chassis, so most suspension, drivetrain, and bushing parts interchange — always confirm against the listing's fitment notes and check your year and model before ordering.

Do I need a tune after installing exhaust parts?

A cat-back exhaust alone generally does not require a tune, but anything changing airflow before the catalytic converter — downpipes, intakes, turbo upgrades — should be paired with a proper tune to keep the engine safe.

How difficult is installing coilovers or lowering springs?

Moderate. A home mechanic with jack stands and basic tools can do it in a day, but an alignment is required afterward. Many owners discover seized or rusty bolts on 20-year-old cars, so budget extra time for that.

What should I inspect on an older GD WRX before modifying?

Check for rust on the rear quarter panels, strut towers, and subframes; confirm timing belt service history; and inspect turbo and gasket condition. Fixing worn maintenance items first makes every performance part work better.