Audi RS6 C5 GIAC Performance ECU Software UpgradeGIAC performance software helps you extract the maximum potential from your Audi RS6 4. 2TT. Power gains have been measured at: 42 wheel horsepower and 78 wheel torque on 91 octane Estimated crankshaft power output of 506 horsepower and 532 lb. ft. of torque Additional performance gains will be seen with upgraded hardware, such as intake and or downpipes. Other benefits to GIAC performance software include: Improved fuel economy Improved throttle