Using a lower octane-rated petrol, such as the standard 95 RON "Premium" unleaded will reduce the engine power output, and have logical reduction in performance.

For the C5 RS 6 powertrain detail, the engine is an all-aluminium alloy 4,172 cubic centimetres (254.6 cu in) twin-turbocharged ('biturbo'), double overhead camshaft, 5 valve per cylinder version of Audi's 4.2-litre 90° V8 petrol engine (parts code prefix: 077, identification code: BCY), developed and manufactured in Germany and the UK by quattro GmbH and Cosworth Technology (now known as MAHLE Powertrain).

With the addition of the two turbochargers (one per cylinder bank), the power output of the V8 engine was increased to 331 kW (450 PS; 444 bhp) at 5,700 to 6,400 rpm, and generated 580 N⋅m (428 lbf⋅ft) of torque.

The combination of the 4.2-litre V8, variable inlet valve timing, and twin turbochargers gave the RS 6 an exceptionally wide power band, with peak torque available from 1,950 to 5,600 rpm.

Further detail of the engine includes fully sequential electronic multi-point fuel injection with intake manifold-sited fuel injectors,[4] mapped direct ignition system[5] with solid-state high voltage distribution using eight individual single-spark ignition coils and NGK longlife spark plugs, and three knock sensors.

It has "hill-detection" capability, and despite many press articles stating that the gearbox was programmed to "blip" the throttle for downshifting gear changes, no UK owners have ever found this feature to be present.

The torque from the engine is first routed from the gearbox output shaft to the Torsen centre diff, and then automatically divided and apportioned between the front and rear axles.

"Anti-Slip Regulation" (ASR), more commonly known as traction control system[7] completes the Bosch ESP-related driver aids.

Utilising the same fully independent four-link front suspension, and double wishbone rear, as its related A6 and S6, the RS 6 was lowered by 20 millimetres (0.79 in), with a 30% stiffer spring rate, and 40% increased compression damping.

The DRC system is mainly mechanical, and uses a pump to provide additional pressure to individual dampers (shock absorbers) during cornering, acceleration or braking; to counteract rolling and pitching.

The system can adjust the stiffness at each individual damper constantly; to maintain both a comfortable ride on straight roads, and a high level of poise and grip when cornering hard, accelerating, or braking.

The DRC's main advantage is that it operates without the need for complicated electronics, as required in similar systems from Mercedes-Benz and other competitors.

Its main drawback is that the DRC dampers have been known to fail (leaking fluid from the cross-linked circuits), which can affect the handling and ride quality of the vehicle; some owners have reported needing multiple replacements of faulty DRC units and many drivers have opted to replace the system with simpler and more reliable aftermarket coil-over suspension.

The last three digits of the Vehicle Identification Number (VIN) are reproduced on a plaque inside the car, displayed on the centre console.

[10] Once again, the special race derivative of the twin-turbo V8 engine was developed and manufactured in the UK by Cosworth Technology (now known as MAHLE Powertrain).

Constructed from steel in a monocoque (unibody) design, the RS 6 uses lightweight aluminium for its front wings (fenders) and bonnet (hood).

It also had no front fog lights to allow for larger frontal air intakes (for the two side-mounted intercoolers (SMICs), and additional radiators).

The ten (per side) front light-emitting diode (LED) daytime running lights (DRLs) are located within the main headlamp housing on the RS 6 in order to increase the size of the air intakes, whereas similar LEDs (but five per side) on the related S6 are found adjacent to the fog lamps in the lower front bumper.

The facelifted Audi A6, released as a 2009 model, received similar front and rear-end LED lighting styling to that pioneered on the RS 6.

The gearbox is set by default, in conventional automatic mode, to delay up-changes during acceleration, and change down earlier to maximise engine braking.

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.

This latest incarnation of the Torsen Quattro, first seen in the B7 RS 4, can automatically dynamically apportion up to a maximum 100% torque to the rear axle, or up to 80% to the front, dependent on traction conditions.

EDL is a part, or "function", of the Bosch ESP 8.0 Electronic Stability Programme,[8] which also includes "Anti-Slip Regulation" (ASR) traction control system.

The system is mainly mechanical, using a pump to provide additional pressure in the diagonally linked dampers (shock absorber) during cornering, to counteract rolling and pitching.

Optional "Audi ceramic" Carbon fibre-reinforced Silicon Carbide (C/SiC) composite front brakes are available, only with 20-inch wheels, which use 420 mm (16.54 in) diameter by 40 mm (1.575 in) thick drilled, vented, and floating SGL Carbon composite discs, with grey painted eight-piston fixed Alcon monobloc alloy calipers with the "Audi ceramic" logo.

As with the previous generation, the new RS6 is powered by a 4.0-litre twin-turbo TFSI petrol engine, now boosted by a 48V belt alternator/starter mild-hybrid system, which can recover up to 16 bhp (12 kW).

Under the new Euro-7 emissions law, Chairman of the Management Board of Audi, Herbert Diess recently said "The RS range set will be the biggest change in the production line since 2004.

The new RS range is set to be in Australia and is said to have a three-cylinder hybrid plug-in, also currently being taken on by Mercedes Benz in order to comply with the new Euro-7 emission law.

Exterior highlights include Nogaro Blue pearl effect exterior paint with body-colored mirrors, black optic roof rails, front grills, spoiler, side trim, and rear diffuser, red brake calipers, 22" silver cast-aluminum wheels, and an RS sport exhaust with black tips.

Interior Highlights include carbon twill structure inlays, Audi Exclusive Valcona S sport seats, lower seat panels, leather interior elements, and RS floor mats all with Denim Blue contrast stitch, and an Audi Exclusive steering wheel with Denim Blue contrast stitching.