APR Audi RS4 (B7) 4.2L FSI V8 ECU Upgrade Automobile Magazine Review of APR Software APR is pleased to present the ultimate ECU Upgrade for the Audi B7 RS4 4.2L FSI V8 engine. After months of long nights and many hours of testing, development and more testing, we are pleased to offer you an ECU recalibration that is second to none.
Show your APR pride with our APR Tuned badges. Our badges have a polished chrome finish to keep a factory-like look over the years. The badge is approximately 70 mm (2 3/4″) long and 38 mm (1 1/2″) tall, and nicely replaces the stock engine designation badge on the back of the car.