Audi S6
Audi made a high-performance, 4.2-litre V8 engine (parts code prefix: 077, identification code: AEC) with a Bosch KE-Motronic ECU available as an option in the original European S4s, and made the decision to continue to do so with the S6, making a version of the 4.2 available as an optional upgrade over the 2.2-litre inline five-cylinder turbo. Unlike the five-cylinder turbocharged version, the V8-powered S6 was supplied with a four-speed automatic transmission as standard, but kept the quattro four wheel drive. A six-speed manual gearbox was also available as an option.
Audi RS 6
Drive output passes through a modified ZF 6HP26A six-speed tiptronic automatic transmission. The parts code 9is 09E and the identification code is KZQ or KZH. The gear ratios are: 1st: 4.171, 2nd: 2.340, 3rd: 1.521, 4th: 1.143, 5th: 0.867, 6th: 0.691, with shortened shift times, with "Dynamic Shift Programme" (DSP) and "Sport" mode. It has paddle-shifts mounted behind the flat-bottomed steering wheel, similar in design to the Audi B7 RS 4. The gearbox is set by default, in conventional automatic mode, to delay up-changes during acceleration, and change down earlier to maximise engine braking. Downchanges in all modes of operation include the Powertrain Control Module electronic control unit (ECU) "blipping" the Bosch "E-Gas" drive by wire throttle, for smoother shift changes. The hydraulic torque converter includes a lock-up function in all forward gears, and is able to completely disconnect when the vehicle is stationary, thus saving fuel.