76mm Mandrel-Bent Cat-Back Exhaust System

The APR Cast Downpipe System is engineered to replace the restrictive factory downpipe and chambered resonator with a larger, 76mm stainless steel mandrel-bent system. This performance upgrade features an ultra-smooth bell-mouth investment-cast inlet for optimal flow transition from the turbocharger's outlet. Constructed from T304L stainless steel, the system utilizes argon back-purged TIG welding for clean, strong welds both internally and externally. It incorporates a GESI high-flow, 300-cell catalyst designed to reduce emissions, smell, and noise without a significant performance penalty. The midpipe section eliminates the front resonator, contributing to a slightly more aggressive exhaust note and removing performance restrictions. Key features include an OEM-style internally-corrugated flex section for engine movement, investment-cast secondary oxygen sensor bungs for a precise fit, and OEM-style low-profile slip-on clamps that simplify installation and ensure clearance. The system is designed to be compatible with the OEM catback exhaust via a removable T304L stainless steel reducer. Performance gains are estimated at +40-47 HP and +36-45 FT-LBS over APR Stage I for the B8 A4 2.0T. This product is intended for race use only and requires a specific waiver form to be completed and submitted before shipping. It is not to be installed on any registered vehicle intended for road use due to potential conflicts with the Federal Clean Air Act. All necessary hardware and instructions are included for installation.