Exhaust Muffler Downpipe System for Subaru WRX & WRX STi (2002-2007) 2.0L 2.5L EnginesHigh Flow T 304 Stainless Exhaust System for 2002 2007 Subaru WRX STi (EJ20 EJ25 GD GG) What it Does: This comprehensive turbo back exhaust kit replaces the restrictive factory up pipe, downpipe, and cat back sections to maximize exhaust gas velocity and reduce backpressure on the turbocharger. The Stock Weakness The OEM exhaust system on the GD and GG chassis Subaru is engineered primarily for noise suppression and emissions, creating significant