Audi S4 Wagon with a Twin-Turbo V8 This Audi S4 (C4) wagon was built by WALAS MotorSport in Mokrawica, Poland. Under the hood sits a 4.2 L V8 (ARS) from an Audi A6 (C5) flanked by two GT2871 turbochargers producing 587 horsepower and ...