The RS6 hints at its fearsome capabilities via a reworked exterior. The rear view that rivals may be forced to get used to is dominated by two huge oval exhausts set into each end of a diffuser that's cut into the bumper. At the front, the cooling ducts of the A6 base vehicle are super-sized and the wheelarches flare dramatically around the standard 19" wheels. Chromed mirrors and side skirts complete the effect. It's a rather low key look when you consider the monumental firepower under the bonnet but Audi's RS models have always done a good line in understated aggression. It's menacing rather than in your face.
There's more to the RS6 than its engine. The S6 chassis has been extensively re-worked with the introduction of revised all-hydraulic version of the Dynamic Ride Control (DRC) system found previously in the old RS6 and the RS4. DRC allows the driver do adjust the RS6's damping through a three-stage system with comfort, dynamic and sport settings. It progressively stiffens the suspension for a more focused driving experience when required or eases off to enhance ride comfort.
The ESP system on the RS6 has been programmed to make late interventions, allowing the driver scope to enjoy the car's handling characteristics to the maximum. The system will brake individual wheels and modulate the engine's power output to rescue the situation if it detects that the driver has lost control but it's been specially designed to give the enthusiastic RS6 owner room for manoeuvre. Those who find even this set-up intrusive can turn the whole thing off entirely but on your head be it. Braking is by a high-spec set of ceramic discs designed to resist fade and stand up to the taxing job of bringing this substantial vehicle safely back from the extreme velocities it's capable of.
The RS6 has gained a reputation as a quite extravagantly expensive car to run. I once interviewed a wealthy chap with an extensive car collection that included a Ferrari F40 and a Koenigsegg who used an RS6 Avant as his daily driver but was selling it because the day to day bills were so large. He raved about the car but was offloading it nonetheless. By the time this second generation RS6 was launched, Audi had ironed out the suspension woes that plagued its predecessor, but one issue that crops up again and again is the fact that the RS6 has a ravenous appetite for brake pads. The engine and gearbox are tough things and those with really deep pockets can take things further still.
The APS Sportec Stage Two conversion has proven popular, consisting of an ECU remap, complete with performance optimisation of fuelling, ignition and boost parameters, in parallel with the fitment of emissions compliant sports catalysts. Post conversion this increases the RS6's outputs to a fearsome 700bhp (515kW) at 6200rpm, allied to 800Nm (584lb.ft) between 3000-6200rpm.
Whichever RS6 model you choose, check carefully for signs of uneven tyre wear and ensure that the expensive aluminium front end isn't showing any dints. There have been reports of headlamp alignment issues, the wheels are terrifyingly easy to kerb but the interior wears well.
(based on a 2009 RS6 Avant - ex Vat) Tyres are around £250 a corner and you'll need to spend around £300 on a replacement clutch assembly, while brake pads are around £150 for the front pair and £100 for the rears. Door mirrors are £150 per unit and the desirable Brembo brake upgrade retails at £1600.
The engine in question is a version of the V10 that was already found in star cars like the Lamborghini Gallardo and Audi's S8 flagship. A bored-out version also appears in the R8 V10 supercar. The S6, the 429bhp model demoted to the role of understudy by the RS6's arrival, uses a version of the unit too but like the RS, its engine is normally-aspirated. In the RS6, the thunderous V10 uses turbocharging to achieve its phenomenal power output and, just for good measure, Audi have thrown in a pair of them. This was the most powerful car Audi had ever built. Oh and the Avant version has up to 1,660 litres of luggage space.
The 572bhp courses through the quattro all-wheel-drive transmission at 6,250rpm and just as astonishingly, the 650Nm maximum torque is available from 1,500rpm all the way up to 6,250rpm. If you spot an RS6 on the road and fancy giving it a run for its money away from a set of traffic lights, be warned. The car will pass the 62mph barrier from a standing start in 4.6s. To live with that kind of punch, you'll need to be at the wheel of something like a Ferrari F430 or a Porsche 911 GT3 RS. Anything from an Aston Martin DB9 down need not apply.
To underline the supercar-slaying performance of the RS6 - this is a full-size executive saloon or estate car remember - it can reach 124mph in 14.9s. If the 155mph electronic limiter wasn't installed, most drivers would run out of race track and nerve well before the RS6 ran out of steam. The twin turbochargers and a series of component modifications are responsible for the power boost enjoyed by the RS6. The gears are shifted through steering wheel paddle shifters connected to a six speed automatic gearbox and an upgraded quattro 4x4 system has the unenviable task of putting all that power down onto the road.
The Audi RS6 is a used car that merits very careful selection. It's a buyer's market at the moment, so steer clear of anything that hasn't been meticulously looked after with a service record that is flawless. You should be able to carve a decent discount from whatever's being asked, but even if you get a bit English and pay full list, you'll end up with not so much a car and more a force of nature. The V10 engine makes the RS6 feel exotic and distinctly out of the ordinary and the unrelenting thrust is otherworldly. It'll be a while before we see the likes of it again.