Audi S6 Tuning Box Kit Improves Horsepower on the 4.0L Twin Turbo VRTuned.com May 16, 2016 Product Info Audi's 4.0L twin turbocharged engine that is found in the new S6 is a menacing beast with 420bhp stock. Audi S6 Tuning can yield some very impressive gains via a ECU flash or tuning box. For those looking to...
