We like
Performance, adhesion, standard features

Room for improvement
Lack of individuality, Tiptronic gear selection, lack of extra performance over A6 V8

WE should be proclaiming the entrance of the missing piece in Audi's S-car puzzle. The quintessential A6. A show of unswerving loyalty to performance, handling and prestige.

But in many respects, Audi already has an S6 in the form of the A6 4.2 quattro.

A powerful V8 engine, provocative nose, lower stance, wider track, fatter tyres, flared wheel arches, clear-glass Xenon headlights, all-aluminium suspension, new lightweight body panels and bucketloads of equipment - the S6 has all of these, passed on from the V8 A6 introduced here 12 months back.

Of course, Audi has made some improvements on the theme to ensure the S6 tag will stick. But is it enough? Enough to separate it from the A6 4.2? Enough to topple established super sedans the calibre of the BMW M5?

In visual terms, the S6 fails to step out from the A6 4.2's shadow. The revised grille, "Avus" six-spoke alloys, aluminium external mirror casings, body-coloured side sills, S6 badges and the pair of visible stainless steel exhaust tailpipes are insufficient and tame.

On the inside, too, there is much to remark upon but nothing to savour, save perhaps for the standard fitment of sat-nav, telephone, heated Recaro leather front seats and a sunroof. The red lighting across the dash and instruments can be had on a $35,000 A3. The S6 at launch in Australia was $166,000.

Quite rightly, we suppose, the S6 investment concentrated on engine performance and improved vehicle dynamics.

While outright acceleration is still behind the M5 or the E55 Benz, for example, two tenths of a second have been lopped off the claimed 0-100km/h time, achieved with the standard five-speed semi-automatic transmission.

Sir can now reach Australia's predominant open-road speed limit in 6.7 seconds.

Whether around town or on the racetrack, the driver will appreciate the improved performance from the high-tech 4.2-litre 40-valve V8. Where the A6 4.2 develops 220kW at 6200rpm and 400Nm of torque between 3000 and 4000rpm, the S6 delivers more of everything: 250kW at 7000rpm and 420Nm at 3400rpm, thanks in no small part to the fitment of high-lift camshafts, retuning of the variable intake manifold and use of a freer-flowing exhaust.

The four-wheel drive family sedan still weighs a stoutly 1760kg, even after new aluminium subframes front and rear lopped off about 11kg, however, the impressive power and torque figures ensure the S6 comes out punching as soon as the driver squeezes the accelerator.

The car feels quick - damn quick - when asked to deliver, providing a stirring deep-throated engine note in concert with the superb acceleration, and not the slightest evidence of torque-steer as all those Newton-metres escape through the wheels to the ground.

The abundance of bottom-end and mid-range torque brings great engine flexibility - no more than a dab of the throttle is required to execute an overtaking move - and while the top-end of the rev range isn't often used, when explored the engine shows no less vigour or refinement.

It makes a grand pairing with the automatic transmission. Left in drive, the adaptive auto shifts seamlessly through the gears and, pleasingly, shows no tendency to go a-hunting for another ratio when the road calls for the driver to frequently move on and off the accelerator. It holds a gear and waits.

In Tiptronic mode, the gears can be changed from either the steering wheel or the centre console shifter. It will block a shift if it deems the resultant rpm too high, and though it will hang on to a gear at high revs, the sequential manual more or less makes its own mind up about the appropriate shift point. It's not the quickest mover between gears, either.

The brakes hold their end up, we're pleased to report, hauling the big car back from high velocity with first-rate control and effectiveness. Only the heaviest of heavy, repeated stops will see them fade.

As a performance car and luxury sedan rolled into one, the S6 has a tough job finding the perfect ground. But get out of the leafy suburban streets and in amongst the tall timber and it will reward like few other plush sedans on the market.

Sitting 10mm lower than the low A6 4.2, and benefiting from a modified and retuned suspension, the car maintains excellent balance and body control through corners and an accomplished ride over smooth surfaces.

Yet these same conditions also deliver some of the best and worst aspects of the S6 package.

The handling is as disciplined as ever, the quattro permanent four-wheel drive - overseen by the effective, non-obtrusive ESP stability control system - keeping the car glued to the playing field.

But while the wide, low-profile tyres also do their bit in providing glutinous grip, they send up an appalling symphony of squeal when cornering over billiard-table bitumen. And when the potholes et al finally turn up - and they always do - the ride can border on being harsh.

The steering is direct but feels too light at higher speeds and fails to provide much in the way of feedback to the driver. What does get back is a small amount of vibration and kickback at times, which generally arrives when the front wheels meet those good old-fashioned road imperfections mid-corner.

The turning circle is also a cumbersome 11.7 metres.

Though it lacks intimacy with the demanding driver and raw appeal, the S6 has most of the traits of a bona fide super sedan, not least of which is a generous, opulent experience for all occupants.

The driver's seat does not have a memory function, however, the front Recaro buckets offer the full gamut of electric adjustment (including lumbar) and provide great support under the ribcage. The suede upholstery also gives better grip than the run-of-the-mill cowhide.

Suede also finds its way onto the doors, pillars and roof, while carbon-fibre (or burr walnut, if Sir pleases) runs along the dash, centre console and doors.

It all feels like a luxurious, costly A6. The trademark powerful, aural Bose CD stereo is there, along with the typically high number of storage facilities, airbags, (effective) dash controls and rear seat amenities.

It's a well-sized, practical beast, too, though the fixed-position aerial on the left-rear rump is unsightly.

The sat-nav system is a relatively simple device to use and its screen tilts to enhance driver or front passenger visibility.

The same can't be said for the in-car telephone, which hides in the box beneath the centre armrest (which is best kept upright for unrestricted access to the centre console). Answering the phone manually requires the box to be opened and an awkward movement of the arm is required to reach the handset apart from the aforementioned Tiptronic buttons, no controls are placed on the standard three-spoke steering wheel.

Standing alongside the A6 4.2, it's the addition of these all-encompassing and (in some cases) exclusive appointments - and the prestige of owning an S-car - that is likely to sway the prospective buyer toward the S6.

But those after the consummate performance sedan need look no further than the BMW M5. It's still the greatest.