APR develops and manufactures hardware, software, calibration & data-logging tools for engine and transmission controllers, including intakes, exhaust systems, intercoolers, turbocharger systems, suspension, brake systems, wheels, and more.

With more than four years' worth of RS4 supercharger engineering research, development and testing, APR’s new Stage III+ TVS1740 Supercharger System represents the pinnacle of Audi’s German engineering enhanced by APR’s American ingenuity.

Fits most APR ECU/TCU supported vehicles (Audi, VW, Porsche, Bentley, and Lamborghini). See application guide.

APR is proud to unveil the Full Intake System for the Audi RS4 and RS5 (B9) 2.9T EA839—an all-in-one solution designed to deliver maximum airflow, enhanced turbocharger efficiency, and real, measurable performance gains.

The APR Stage III+ TVS1740 Supercharger System fills the void by adding an average of roughly 88% more horsepower and torque across the entire power band. The results are nothing short of amazing; taking the RS4 from 414 horsepower to 626 horsepower on pump fuel and 688 on race fuel without breaking a sweat!

APR’s 4.2L FSI V8 ECU Upgrade is an expertly recalibrated engine control strategy that primarily remaps the engine’s air fuel ratio and ignition timing, within the factory ECU, to provide smooth and reliable power as if intended by the OEM.

Feb 5, 2025 · APR is proud to unveil the Full Intake System for the Audi RS4 and RS5 (B9) 2.9T EA839—an all-in-one solution designed to deliver maximum airflow, enhanced turbocharger efficiency, and real, measurable performance gains.

The APR Stage 1 ECU Upgrade is the first step towards tuning your engine. It produces up to 444 HP and 372 FT-LBS of torque. APR Stage 1 is available for 91 AKI, 93 AKI, and 100 AKI in North America and 95 RON, 98 RON, and 104 RON in the Rest of the World.

Dec 7, 2008 · This is my personal account of the APR ECU experience for the B7 RS4. Some might know my car, for those of you who do not, it is a B7 2008 RS4 with roughly 35000 Kilometers on the clock. The car has been completely de-gunked in February by manually cleaning the accessible parts and chemically cleaning the parts inaccessible.