#02#Audi is enjoying a major upturn in its ability to produce sporting cars. On the back of the RS4 and the promising first impressions of the new TT the marque appears to have turned the corner; and it needed to. In the face of the onslaught from BMW's M-division and AMG, Audi had to raise the game.

The new Audi S6 rides into the domain of the finest large sporting saloon money can buy, BMW's M5. Nonetheless, despite being equipped with a V10 engine and a price ticket approaching that of the M5 it is quickly obvious that the S6 does not intend to get into a toe-to-toe slugfest with the M5.

Let's make this very clear: from first clapping eyes on the Audi S6 through to throwing it down our favourite roads, we knew that the BMW M5 is not going to be pushed by the S6; not dynamically at least. The understated appearance of the Audi is great. It may have big alloys and that bold corporate face, but the clues to its true identity are well concealed. The rows of LED lights under the headlamps are a real giveaway at night and no doubt useful for clearing the outside lane of the Autobahn, but the only other visible cues are in the subtle badging on nose, tail and brake calipers, two small V10 badges on the flanks and the four tail pipes.

In the test car's metallic silver paint the other giveaway (polished silver mirrors) is disguised and the whole car is a very subtle and discreet package. Bear in mind that in that long nose nestles the heartbeat of a Lamborghini Gallardo; at least the main part of it. It has been sobered slightly and wears the Le Mans proven FSI hardware familiar on most Audis now, but power is a still serious 429bhp, placed neatly between the RS4's 414bhp and the S8's 444bhp, the latter produced using the same base engine.

Upon turning the key there is a tantalising pause before the engine cranks over and then a lovely burst of noise as the engine catches and revs to around the 2000rpm before settling to a deliciously snorty idle. For the first thirty seconds or so after a cold start-up the engine spits and snarls; we guess that this is something to do with the need to warm the catalysts quickly, but will openly admit we stood behind the car enjoying it. #p##02# On the road the 5.2-litre V10 combines marvellous low rev flexibility with searing top-end urge. All but inaudible under light load, only when pushed through the 4000rpm mark does the V10 give away its roots as a supercar powerplant emitting a hard-edged roar as the crank speed increases. It is something of a shame that during our time we noted it sounds even better on the outside than it does to the occupants; we though an RS-style "S" button may have been a wise inclusion to control a by-pass valve in the exhaust system.

The six-speed automatic 'box is a conventional auto' with torque converter and a Tiptronic shift operated via the lever or paddles behind the wheel. It shifts seamlessly in auto mode and performs full throttle shifts equally smoothly when pushing on. Our only reservation was with the all-or-nothing lock up when moving off. Even after a week and many hundreds of miles worth of practice we couldn't move off at any other than a crawl or a bolt.

The Audi S6's handling is biased appropriately towards the sporting and it does a fine job of traversing our most sinuous of test routes displaying some good body control and plenty of grip. It isn't exciting, involving or standard setting in any way but it is competent whilst lacking the dynamic envelope of some rivals, with nose led understeer always the dominant attitude if you push beyond its limits. The brakes always have the power to rein in the horses and resisted fade well. However, the S6 doesn't shrink around you in the way a more capable car does (such as the M5 would) and often feels a little heavy; and it doesn't goad or excite like an M5 does.

Most surprising was the ride quality of the S6. Almost at odds with what appears to be its comfort bias the S6 suffers from an unsettled feel, even on the motorway where it would be safe to assume such a car would accrue the majority of its miles. Expansion gaps and ridges intrude more than expected and upset the car much more than they should; and the ride around town over drain covers and pot holes is disappointing. #p##02# We've raved about the A6's interior previously when we drove the Allroad down to France earlier this year and the S6 shares much of that layout and design. The MMI screen dominates the dash and is intuitive and easy to use. The minor controls are well positioned and all operate with clinical efficiency. Carbon fibre on the centre console, dash and doors allude to the sporting pretensions. Electric heated seats with a good range of adjustment cosset those up front whilst passengers in the rear lounge in an expanse of space, all subtly back-lit via adjustable lighting in the footwells and armrests. Accommodation as a whole is generous; the boot is one the biggest we've encountered.

Living with the Audi S6 was utterly painless. It represents typical Audi efficiency coupled with the naughty excess of an Italian V10 beneath the bonnet. Although we noticed the service intervals are actually quite long suggesting this is one Italian that has had one figment of its tempestuous persona mellowed. Though as you'd expect, the thirst for unleaded is pronounced; we managed an average of almost 20mpg in mixed driving, but in context that betters competitors such as the M5 and Range Rover Sport. The S6 is a well rounded package; hugely comfortable, spacious, quick and discreet it does almost all that could be asked of such a car and is a very desirable daily drive.

It's worth noting that even given the power, performance credentials and the pricing we can't help feeling that Audi has held a little back here. There is certainly room for an RS6 range-topper with the harder edged ethos of the RS4 and even more performance. Audi's engine range is bewildering now, so it's hard to guess what it has up its sleeve for such a model. We hope that we're right; an RS6 would have enough to begin to finally worry the BMW M5. #p##02#

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Audi A6 saloon UK range overview

- Audi A6 2.0 TFSI SE 6-speed manual: £25,365
- Audi A6 2.4 SE 6-speed manual: £25,425
- Audi A6 2.4 quattro SE 6-speed manual: £27,025
- Audi A6 3.2 FSI SE 6-speed manual: £31,525
- Audi A6 3.2 FSI quattro SE 6-speed manual: £33,125
- Audi A6 4.2 FSI quattro SE 6-speed tiptronic: £44,475
- Audi S6 quattro 6-speed tiptronic: £55,375
- Audi A6 2.0 TDI SE 6-speed manual: £25,275
- Audi A6 2.7 TDI SE 6-speed manual: £27,120
- Audi A6 2.7 TDI quattro SE 6-speed tiptronic: £30,120
- Audi A6 3.0 TDI quattro SE 6-speed manual: £31,570
- Audi A6 3.0 TDI quattro Le Mans Edition 6-speed manual: £34,575