AUDI’S new A8 W12 is perhaps the most symbolic example so far that the German brand is serious about rivaling luxury car leaders like Mercedes-Benz and BMW.

Available here for the first time, the brand’s first 12-cylinder is conclusive evidence of where Audi is positioned in Europe, and would desperately like to be perceived as here: a luxury car-maker equal to its established German opponents.

As Australia’s first taste of the innovative naturally-aspirated W12 engine (as opposed to the twin-turbo version that graces another Volkswagen Group model, the Bentley Continental coupe and sedan) – and a no-excuses rival for super-limos like BMW’s $335,600 760Li sedan and the $355,900 Mercedes-Benz S600L, the A8 6.0 makes a formidable argument.

The same money also buys the AMG-tuned short-wheelbase S55 sedan, while for a whopping $435,900 Mercedes-Benz offers the even more powerful 450kW/1000Nm twin-turbo 6.0-litre V12-powered S65L sedan.

So while the flagship A8’s 6.0-litre W12 produces a mere 331kW and 580Nm of torque, that’s still 4kW up on the BMW’s 327kW 6.0-litre V12, which delivers 20Nm more peak torque at 600Nm and which the top A8 undercuts by more than $10,000.

As such, it’s 5.2-second 0-100km/h claimed acceleration figure is a good four-tenths better than the BMW’s – and its creamy, responsive and supremely satisfying power delivery – all the way to 6200rpm - is accompanied by a lumpy, expensive sounding exhaust note.

The key here is the A8’s alloy chassis, which brings the W12’s kerb weight to a still-lardy 1995kg, compared to the 760Li’s 2180kg.

Somewhere in between is the S600L at 2135kg, but it uses twin turbochargers and a 5.5-litre V12 to good effect, sprinting to a class-best 100km/h in just 4.8 seconds.

This is despite its employment of a five-speed auto, while the Audi and BMW offer six speeds.

Of course, the price of this performance is a $30,000 premium over the A8 W12, which begs the question: would a twin-turbocharged A8 W12, using the Bentley’s 411kW engine, be the fastest in its class and at what price?

While the numbers reveal the alloy Audi to be the lightest and the force-fed Benz to be the quickest, the A8 has a number of other enticements in its armoury.

Perhaps the most significant is its employment of Audi’s qattro all-wheel drive system as standard, the weight of which is largely compensated for by its alloy chassis. But in terms of outright grip and active safety, it clearly puts the W12 a step ahead of its rear-drive rivals.

While the W12’s Servotronic steering is super-light at low speeds and then firms up nicely at speed, it’s also responsive, communicative and remarkably free of the torque steer associated with many vehicles that drive their front wheels, lesser Audis included.

That said, the top-shelf A8’s steering is never as intimate as the other Germans’, which also turn in with less provocation and hold a given cornering line with more finesse.

Like the 760Li and S600L, A8L is 130mm longer than its short-wheelbase stablemates. This is evident in its longer rear doors, which make entry and exit to the spacious rear seat considerably less of an effort.

As expected, all three models also rate highly in terms of morgue-like cabin quietness, impeccable ride quality and standard equipment, including cutting-edge technologies like air suspension, electric parking brakes, adaptive bi-Xenon headlights with washers, automatic wipers and headlights, rear TV tuners, heated and powered rear seats and even self-closing doors.

But while the Mercedes buyer must pay extra for radar-controlled active cruise control, keyless starting, remote bootlid closing, dual-zone rear climate control, tyre pressure monitoring, a rear fridge and rear side blinds, all of this is standard in the Audi.

The A8’s striking exterior design – which is differentiated from lesser models subtly but effectively by extra grille chroming, daytime LED driving lights behind clear headlight lenses, twin trapezoidal exhaust outlets and 19-inch alloys – is as intricately designed as its high-quality interior, which in our eyes has moved ahead of both BMW and Benz in terms of fit, finish and presentation.

Resale value is also a big issue at this level, but Audi goes to great lengths to demonstrate the residual values of its models are equal or better than both its German rivals in Australia.

Next year’s new S-class will no doubt raise the bar again for the lucrative limousine market, which carries a great deal of credibility for all manufacturers.

As it stands, however, the innovative 12-cylinder all-wheel drive Audi flagship is lighter, prettier, better equipped, better value, more exclusive and, arguably, better put together than both of its direct rivals.

Of course, it can be argued the 7 Series and S-class are marginally better driver’s cars and there’s no disputing the fact they carry the badges of more highly regarded marques.

But we suspect those that test drive the A8L W12 and then purchase either of is rivals put the greatest emphasis on these factors and always will.

Finally, Audi has a bona fide competitor in the world's most prestigious vehicle segment.