With additional bolt ons it looks like the 4.0 TFSI will be capable of surpassing 700 at the wheels before anyone even needs to modify the turbochargers. You thought the AMG M157 would be the king of German V8 turbo tuning due to its 5.5 liters of displacement? Think again.
APR managed a 10.6 @ 129 in the 1/4 mile with their RS7 on a Stage I tune. That was accomplished with roughly ~600 wheel horsepower. It looks like the Stage 2 setup on race gas has a shot at breaking into the 9's. Wow.
(before someone tries to be smart and point out why the horsepower and torque do not cross at 5252 it is due to the horsepower and torque being scaled to show max figures)