Price and equipmentWe will get to performance later but even if the RS7 can only match its competitors on pace, its price is possibly the sharpest feature, starting at $238,500 before on-road costs, or about $25,000 less than is closest price competitor, – the Mercedes CLS 63 AMG S.

It is also $60,000 less than the BMW M6 Gran coupe and a whopping $80,000 cheaper than Maserati’s Quattroporte GTS, so on price alone the Audi is off to a good start.

For that cash the RS7 gets a decent amount of standard equipment including Audi’s MMI navigation, Bluetooth, three-zone climate control, WiFi hotspot connectivity, automated parking and adaptive cruise control.

Xenon headlights, night vision, forward collision mitigation, active lane assistance and speed limiter are among the RS7’s advanced standard safety features.

However, the tempting but potentially costly options list can blow the RS7’s price out with little effort.

Our test car had acres of carbon-fibre thrown at the interior for $8500, A gorgeous honeycomb quilted leather interior with red stitching for $13,900 and a sonorous Bang and Olufsen sound system complete with tweeters that rise from the dash – for a hefty $12,000.

With all the extra goodies our car ended up closer to the price of its pre-extras competitors at $277,800.

Our test car was decorated in an attention-drawing Nardo Grey non-metallic paint. Unkind onlookers used the words ’primer’ and ’battleship’. Others were more complimentary, but all were intrigued. Perhaps a car with such unusual looks as the RS7 has to try hard with gaudy colours to get noticed.

InteriorSlipping into the RS7’s driving seat and tapping the aluminium start-button was a ceremony each time, with a bark form the two big-bore tailpipes and the large MMI screen rising from its home in the dashboard.

Tasteful, subtle mood-lighting picks out cabin details without being intrusive and white LEDs spell out the variant name on the sills.

The flat-bottomed and heavily perforated steering wheel is a masterpiece of ergonomics, sitting perfectly in the hands and housing only the most important function switches, while the attractive sports seats grab hold of occupants ready for business.

The interior design is typically Audi and manages to be memorable without resorting to lavish touches, although real (optional) carbon-fibre featured heavily throughout our test car.

On-board entertainment and information systems are fast, intuitive and easy to use with typical German logic, but the absence of standard USB ports a disappointment.

The optional B&O sound system was outstanding with a rich omnipresent sound and almost unhealthy volume, befitting the consistent quality and timeless design prevalent throughout the interior, including the second-row seats.

Room in the strictly two-person rear row is adequate rather than abundant but comfort is not compromised and while the absence of a fifth spot provides ample shoulder room, a jump seat in place of the cup-holders would be handy for shorter trips.

At the back end is a generous 535-litre boot, its slight limitation caused by the falling coupe-esque roof-line made up for by deep dimensions and a capacity that can be increased to1390L by folding the rear seats.

Accessing the boot via the slow electric tailgate was a little tedious, so we would have preferred a more conventional keep-fit version.

Engine and transmissionUnder the bonnet of the RS7 lies exactly the same twin-turbocharged V8 found in the big-booted RS6 Avant, but with only 4.0-litres at its disposal you would be forgiven for thinking it couldn’t possibly keep up with the likes of the 4.4 and 5.5-litre force-fed engines in its BMW and Mercedes comparable performers.

But masses of power only results in usable performance if it can get to the road effectively and that’s where Audi’s famous quattro all-wheel drive system comes in to play.

With 412kW and 700Nm of torque the Audi might not match the other Germans on output, but limited by two-wheel drive the M6 and CLS 63 AMG lose in the 0-100km/h stakes when pitched against the all-paw Audi.

Acceleration off the line can only be described as savage.

All four 21-inch wheels find grip wherever they can and rarely does the ESC have to interrupt proceedings, resulting in constant and repeatable acceleration to 100km/h in 3.9 seconds, where many two-wheel drive solutions work on a case by case basis.

The RS7 engine is one of the most surprisingly lag-free turbocharged engines we have had the pleasure of pointing our right toe at and it allows the same fabulous pick-up across the rev-range.

While the turbos have unfortunately robbed a little of the raw V8 exhaust note, the lively engine still manages to create an almost Group-B rally sound-track on overrun, firing off loud rifle-like cracks and snaps when throttle is closed.

An eight-speed Tiptronic transmission is the only option for dealing with the substantial power and it fulfils its role well.

Where many double-clutch transmissions struggle at low speeds, the RS7’s torque converter unit allows smooth uptake, even in its sportiest settings.

Despite the enormous torque on tap, clicking an upshift in paddle before the 7000rpm redline results in silky smooth cog-swaps. But if the upshift cue is missed, the engine cuts power at the limiter until the next gear is selected, reintroducing power with a hammer-blow to the back bumper and a glorious clatter of exhaust complaint.

We almost preferred the theatre of the latter, which provided a slower rate of progress but an infinitely more memorable experience.

Audi says the mighty powerplant is capable of fuel efficiency figures of below 10 litres per 100 kilometres, but during a variety of driving styles we managed a figure of 13.5L/100km.

Ride and handlingWhile the RS7 might be largely similar to the wagon RS6, the Sportback is more mach-speed executive rather than B-road bread van, so offers a marginally more compliant chassis.

In town the Audi is easy to live with, resisting tram-lining over irregular surfaces and only transmitting the largest lumps in to the cabin. Its long wheelbase and plunging bonnet line made manoeuvring a little trickier than some but above all it felt like any other large sedan.

Out on the flowing country roads is where the RS7 belongs though.

Attacking fast long bends was effortless with bountiful grip from the 21-inch optional gloss-black wheels and famous quattro transmission system.

Steering feel and feedback was a little on the light side and most of the communication form the road came via the excellent driver’s seat. Turn-in was sharp and fast with the tail following obediently but heavy handed instructions highlighted the RS7’s size and 1920kg weight.

In sharper low-speed cornering weight would roll on to the front outer wheel, even with careful power application and it was tricky to balance the two ends of the car.

A good mid-corner stab of the throttle would cause the front wheels to complain but the lightning ESC system would manage power distribution despite our best efforts to upset it.

Settling in to a longer straighter journey was a pleasure aboard the RS7 and not much could phase its impeccable freeway manner. Weather conditions, road surface and speed limits do not dictate the Audi’s ability.

The RS7’s air suspension insulated occupants from sharp bumps and noise equally well.

We loved the firm but comfortable sports seats but with runaway performance, a careful eye had to be kept on the head-up display whenever the cruise control was turned off. Oh for an Autobahn or unrestricted Northern Territory strip of asphalt.

Safety and servicingDespite its high output, the RS7 has relatively standard service intervals of 15,000km or 12 months and comes with Audi’s three-year unlimited kilometre warranty, while corrosion is guaranteed to stay at bay for 12 years.

Airbags total six, while all the usual safety features are included from ABS, ESC and EBD plus some extras like torque vectoring and six-pot front brake callipers on 390mm discs as standard.

VerdictWe loved virtually everything about the Audi RS7’s outlandish performance from the way it catapulted to staggering speeds from a standing start, through its sure-footed quattro grip, to the accompanying theatrical soundtrack. But the spectacular five-door might be overqualified for Australia.

It is only at speeds nudging the national limit that the RS7 starts to come alive and prove what 412kW/700Nm with a transmission system to handle it can really do, and we feel that makes Audi’s fastest Sportback somewhat of a caged beast.

At lower speeds and a more sedate driving style, the RS7 performs admirably with a comfortable ride and reasonable fuel economy, but so too do the lesser S7 and A7 variants for a lot less cash.

But if you feel you can exploit one of Audi’s fastest ever models within the confines of the law, or you have access to some ungoverned stretches of blacktop, then the RS is the bargain of the super coupe-sedans.

RivalsBMW 650i Gran Coupe ($237,975 before on-road costs).

BMW’s M-powered version of the Gran Coupe has RS7 rivalling performance but as its price blows the budget out to nearly $300,000, the more sedate normally aspirated variant is more comparable. As a result, the BMW offering falls behind on performance and traction with only two-wheel drive but those 6-Series looks are still knee-weakening.

Mercedes-Benz CLS 63 AMG S ($262,650 before on-road costs).

With a monstrous 5.5-litre twin-turbo V8 the Mercedes blows everything out of the way with power and torque, but due to right-hand drive conversion problems, it is not available with the all-wheel drive system of left-hooker markets.

Porsche Panamera S ($289,400 before on-road costs).

Porsche offers a pricey way to get into the coupe-sedan market and its S variant does provide a V8 soundtrack uninhibited by turbos, but the associated reduction in power makes it lag behind the Audi in performance. Quintessential Porsche build quality partially justifies the high price.

Maserati Quattroporte S ($240,000 before on-road costs).

Like the BMW, Maserati’s most powerful GTS Quattroporte can’t compete with the Audi on price so its middle of the range V6 turbo has to do. Its cavernous rear seat space makes it the second-row comfort champion but it can’t keep up with the Audi’s aggressive performance.