RS4 Avant Tuning is done here at Vivid Racing by Unitronic, APR, REVO, GIAC, Upsolute, Powerchip, and our own VR Tuned. The Avant is the wagon variant of the Audi A4 and A6. The USA did not get the 2.7L Twin Turbo B5 RS4 or the B7 V8 RS4. However we do offer the ECU tuning for the RS4 Avant models for European owners or those that may have the car grey market here in the USA. The ECU tuning on either chassis can definitely improve the cars horsepower and torque. The V8 throttle response becomes much more alive and the car pulls harder through the redline. Much like the USA B5 S4 2.7T, the RS4 turbo gets an increase in boost as well as tweaking of the fuel mixture and timing to gain it almost 80 horsepower over stock. You can view all our Audi ECU Tuning Here.