AUDI S6/RS6 (1999-2004)
Audi?s R series of cars occupy a narrow but well-defined niche. Not quite as focused as BMW M cars nor as powerful as the heaviest hitting AMG Mercedes models they nevertheless offer serious performance with impeccable build quality. If you feel the need to ramp the intensity levels up a notch or two higher, Audi also offer the premium sports RS models. The suave Audi A6 was transformed into 340bhp S6 in late 1999 with the macho 450bhp RS6 following in 2002. These cars were justly popular and as a result there?s no shortage of choice for used buyers.
HISTORY
The inkling that a sporty Audi A6 may be on the way was betrayed by the introduction of the 295bhp A6 4.2-litre quattro models in February 1999. With a longer bonnet than the rest of the A6 range to house a monster V8 engine the A6 4.2 was quick but designed to cater to an executive audience with a whole host of luxury fitments and comparatively soft suspension. Some wondered what the car?s raison d?etre was given that it wasn?t significantly quicker but markedly thirstier than the 2.7T model that Audi already offered. The S6 answered many of these questions but wasn?t unveiled until late 1999, the first cars starting to appear in UK dealers at the turn of the year. With 340bhp on tap it wasn?t the BMW M5 basher that many had hoped for, Audi instead concentrating on a firmer ride, a more aggressive look and feel and a few tenths knocked off the benchmark sprints. Available in saloon and Avant estate it was nevertheless very popular.
The RS6 upped the ante still further with its bigger spoilers and 450bhp punch. It?s worth pausing to put this into perspective. A decade or so back, after the media frenzy that was the 377bhp Lotus Carlton, development of the ridiculously powerful executive saloon was knocked back a few steps ? but not for long. Soon, we had the 340bhp BMW M5, outflanking the 326bhp Mercedes E500. Mercedes answered back with the 354bhp E55 AMG introduced in February 1998, but even this car was soon humbled by BMW?s 400bhp M5 V8. Audi wanted to join the party too, but the 340bhp S6 was rather outgunned by its two homeland rivals and was even further embarrassed when Jaguar entered the fray with their 400bhp S-TYPE R. The RS6 put Audi back amongst the power brokers, its power output humbling fully paid up members of the supercar club such as the Ferrari 360 Modena or the Porsche 911 Turbo. The ultimate RS6 arrived in spring 2004 in the shape of the 280bhp RS6 Plus Avant.
WHAT YOU GET 
Visual clues to the S6's identity are few. There are tiny boot badges, an S6-badged Audi Sport front radiator grille, brushed aluminium door mirror casings, 17-inch Avus six-spoke alloy wheels and twin stainless steel exhaust pipes. In other words, the neighbours need never know. The interior looks and feels the part. The Recaro sports seats are trimmed in a combination of Alcantara (a kind of suede) and soft leather, while the dash and doors get carbon fibre inserts (or traditional wood if you prefer). As you'd expect for the money, equipment is pretty comprehensive (climate control, six airbags, cruise control, electric everything etc, etc), though, if you've more to spend, there are still plenty of options, including a colour TV built into the dashboard. Recent specification improvement include the addition of Xenon Plus headlamps, an air quality sensor and a ?Symphony II? radio with front dash-mounted CD autochanger and cassette.
The RS6?s additional power gives it a far more special feel but there?s no need for heroics at the wheel to make absurdly rapid progress. Tail out thuggishness and uncouth wheelspin has been massaged from the Audi?s dynamic makeup, the electronic control systems ensuring that the car is always comporting itself with utter decorum. Comparisons with BMW?s M5 rather miss the point in this respect, as the RS6 is more akin to a juiced up Jaguar S-TYPE R than the more focused 5 Series. That?s not to say it lacks a wicked side to its personality.
The engine is a gem, the 40-valve Audi 4.2-litre V8 putting in sterling service, in this instance with a pair of light pressure turbocharger thrown into the mix. The low inertia blowers give a wide spread of torque and the correspondingly punchy 9.3:1 compression ratio means the engine never has that typically ?baggy? throttle response that many powerful turbocharged cars have when you catch them with their trousers down, off-boost and off-colour. Beautifully finished and classically understated, the Audi RS6 is effortlessly desirable. If you?ve got the means, this is the car for those who don?t do airline food. Obscene power has rarely been packaged so discreetly.
WHAT YOU PAY
Although Audi have a reputation for delivering cast iron residual values, there can be no escaping from the fact that big, powerful and thirsty cars almost always tend to take quite a bashing when the time comes to sell them on. The S6 models are no exception. An S6 saloon that would have set you back £52,250 in early 2000 will now sell for £18,000 with the Avant versions attracting a premium of around £500. These residuals weren?t helped by Audi?s decision to lop £5,000 off the S6?s retail price in order to make it look a little more competitive in the face of not only a horde of more powerful rivals but also the RS6.
The RS6 fares a little better due to its comparative rarity and perceived speciality nature. 2002 examples are currently changing hands for £48,000 in saloon form and £28,000 as an estate. Both S6 and RS6 models will prove very expensive to insure with most brokers rating them Group 20.
WHAT TO LOOK FOR
Not too much, really. There have been some tales of niggling unreliability but nothing too serious so far. The quattro system is reliable and well proven but it?s best not to allow a local spannerman to fiddle with it.
The complexity of the car should be enough to ensure you insist on an S6/RS6 with a cast-iron service history and, at this stage, Audi dealers are still likely to have the best examples. The premium they charge may be well worth your peace of mind.
Interiors are hard wearing and well designed, much like the rest of the car. As for corrosion, with an Audi you're pretty safe and there's a lengthy anti-perforation warranty to reassure you (ensure any conditions have not been breached by previous owners).
REPLACEMENT PARTS
(based on a 2000 4.2 S6 quattro Saloon - ex Vat) A clutch assembly is around £265. Front and rear brake pads should be about £85 a set. A radiator is about £195, an alternator about £275 and a starter motor £195.
ON THE ROAD
For those unimpressed by the ?mere? 340bhp on tap in the S6, consider this. There's not much point in having huge reserves of power if every time the heavens open, you spin it away on the wet tarmac. Yes of course, the BMW M5, the Jaguar S TYPE R and the Mercedes E55 AMG all have sophisticated traction control and dynamic stability systems but it's not the same as having all wheels driven. The familiar quattro four-wheel drive system in the S6 means that this car will beat its German rivals to any given cross-country destination in anything other than bone-dry conditions.
And even then, it won't be far behind. Sixty is just 5.7s away from rest on the way to an artificially-limited top speed of some 155mph. Which ought to be fast enough for most. And even if it isn't, there are other compensations. Like the fact that the S6 is cheaper ? though of course 'cheapness' is always relative in comparisons like these.
In response to the inevitable question "Was tut sie, Herr?" the RS6?s owner?s answer is an identical 155mph. This is due to the electronic limiter that Audi fit as a result of the gentleman?s agreement to which most major German manufacturers adhere (Porsche apparently are no gentlemen but nobody seems to mind). Remove the electronic nanny and Audi engineers admit that you should see a hugely more whelming 190mph without too much difficulty. Even those who?d have difficulty distinguishing their RS from their elbow have got to hand it to Audi. This car is seriously quick. The 60mph increment will detain you for 4.5 seconds, the RS6?s quattro all-wheel drive deploying the power with a minimum of fuss.
OVERALL
How fast do you want to go? This very much depends on how deep your pockets are. On an objective basis the RS6 is a more impressive car but used choice is limited. The S6 has never created quite such a cult following but as a consequence it appears almost a bargain, a decent used example costing little more than a new Mini Cooper S Works. Both cars are built to last and the massive V8 engines are relatively unstressed. Track down a decent example and you shouldn?t have cause for complaint.
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