We've sampled the Audi S4 on track and have preached the transformation that Audi's new Sport Differential makes to the dynamics of an Audi. We've just stumbled across a video of Ignacio Perez driving a new S4 equipped with the differential on the Jarama racecourse. You can see from the movie that Perez is intentionally pushing the car into drifts, throttle on oversteer that is a new element not available in previous Audis except the R8 prior to the Sport Differential. Enjoy.
Video: The New Audi S4 Drifting at Jarama Racecourse in Spain