The 2002-2005 Audi A4 quattro combines timeless Audi design, turbocharged performance, and legendary all-wheel-drive capability. Enhance your A4 quattro with APR performance upgrades, including ECU tuning, intake systems, exhaust upgrades, turbocharger enhancements, and supporting hardware engineered to increase power, improve responsiveness, and maximize driving enjoyment.

APR’s software and tuning solutions deliver refined performance engineering—precision ECU and TCU calibrations, along with inline modules, that elevate power, transmission response and driving dynamics while maintaining the integrity of your European vehicle’s factory systems.