AUDI has arrived fashionably late to the luxury four-door coupe party, launching its large A7 Sportback - an uber-stylish derivative of the new A6 sedan due on sale here mid-year – in Australia this week.

There are two 3.0-litre six-cylinder versions of the A7 to start off with - a V6 diesel priced at $142,750 and a supercharged V6 petrol model at $147,800 - while a cheaper 2.8-litre petrol V6 will follow.

Mercedes-Benz boldly kicked off the four-seat four-door coupe concept with its dramatically-styled CLS back in 2004 – the same year Maserati’s conceptually similar Quattroporte appeared globally.

Since then BMW has returned fire with the 5 Series GT - and will next year release a coupe-like four-door version of the 6 Series - and Porsche has fired off its own (considerably more expensive) salvo with the Panamera.

According to Audi, the A7 Sportback combines the elegance of a coupe with the comfort of a sedan and the practicality of a wagon.

It introduces a range of new features to the Audi Australia stable, including an optional head-up display ($3400) that projects relevant information such as vehicle speed onto the windscreen – technology that has only been available in top-end BMWs until now.

Audi’s big new hatchbacked cruiser also presents much of the technology introduced last year in its top-shelf A8 limousine, but at a far lower price point.

It also gives Australians a taste of what to expect from the important new A6, which will take on the BMW 5 Series and Mercedes-Benz E-class around the middle of this year.

Built off the new A6 platform, the A7 uses the same five-link front and trapezoidal-link rear suspension systems, with new aluminium control arms. Customers can choose from standard steel springs or optional adjustable air suspension.

The A7 features the same new, more economical electro-mechanical steering system as the new-generation A6, for which engineers have chased BMW with a more direct steering ratio for a more precise feel.

Like its sedan sibling, the A7’s body is mainly steel but has a 20 per cent aluminium content, which Audi says saves close to 50kg. Several panels including the bonnet, doors and hatch are made from aluminium. The weight saving measures prevented a blowout and the A7 weighs in at around a hefty 1800kg.

The big Audi is only slightly shorter than a Holden Caprice, measuring 4969mm nose to tail, but appears even larger because of its long sloping roofline, the highest point of which is just 1420mm. The wheelbase stands at 2914mm.

Despite the curvaceous roofline, Audi says passengers, including those in the two rear seats, have more headroom than the passengers in the back of the current A6.

Luggage space stands at a handy 535 litres, although the boot is quite shallow towards the rear. Audi has catered for longer items of cargo by allowing for the 60/40-split rear seats to be folded down, opening up a massive 1390 litres of space and enabling very long items to be carried. An electric tailgate system is standard, allowing for the hatch to be opened or closed at the touch of a button.

The entry-level A7 engine is the Volkswagen Group’s familiar 3.0-litre TDI turbo-diesel V6 that runs a common-rail direct-injection system. It generates 180kW between 3800rpm and 4400rpm and a healthy 500Nm between 1500rpm and 3250rpm.

Audi says that allows it to dash from 0-100km/h in just 6.5 seconds. The official average fuel economy figure is just six litres per 100km, while the CO2 emissions number is 158g/km.

For those who are up for some Otto cycle action, Audi’s supercharged TFSI 3.0-litre direct-injection petrol V6 – seen in the current A6, S4, Q7 and Porsche’s Cayenne Hybrid - is also available.

This high-performance engine takes the place of the 4.2-litre V8 that is being phased out of most Audi models. It generates 220kW between 5250rpm and 6500rpm and 440Nm between 2900rpm and 4500rpm.

The more potent engine allows for a claimed 0-100km/h sprint time of just 5.6 seconds. It might be faster than the diesel, but also uses more fuel with an official fuel economy figure of 8.2L/100km and an emissions figure of 190g/km.

Both engines employ an idle-stop system to save fuel at rest - a feature that can be switched off.

Both the petrol and diesel A7s feed their torque through Audi’s quattro all-wheel-drive system, which now features a crown-gear centre differential that the company says is far lighter than the torque-sensing Torsen system it replaces.

As before, the new centre diff feeds 40 per cent of power to the front and 60 per cent to the rear in normal conditions, but can feed up to 70 per cent to the front and alternatively up to 85 per cent to the rear depending on the conditions.

Audi’s seven-speed dual-clutch DSG automatic, called S-Tronic, is standard on both cars and can be controlled with the regular gearshifter or the standard paddles on the rear of the steering wheel. No manual transmission is available.

The 3.0-litre diesel A7 sits on 18-inch rims as standard, with 255/45 tyres featuring built-in pressure monitoring. The 3.0-litre petrol model has 19s as standard with 255/40 tyres, while 20s are available from the options list.

The A7’s interior is shared with the upcoming A6 and comprises a waistband that runs around the top of the dashboard. The centre stack faces toward the driver and an eight-inch display pops up out of the dash-top.

Occupants can use the traditional MMI (multi-media interface) control unit, which features a roller-ball with surrounding buttons or can be operated via finger squiggles on a special pad. Interestingly, it even recognises characters of many Asian languages.

A standard media system includes a 60GB hard-drive with 20GB reserved for music. This comes standard with a satellite-navigation system and voice control, and can be paired to your mobile phone using Bluetooth. Four-zone climate-control, with rear controls, is standard.

A range of advanced technological features are available as options, including an infra- red night vision system ($4890) that identifies whether a pedestrian is in danger by highlighting them in either yellow or red, depending on the perceived risk. There is also an adaptive cruise control system that can maintain a distance to the car in front, even stopping and starting again automatically.

The A7 features a range of active safety systems that prepare the vehicle for an accident by, for example, preparing the brakes and shutting the sunroof, and can actively brake the vehicle depending on the specification chosen.

Cosmetically, Audi’s latest new niche model features the new A6-style front-end with single-frame grille and headlights punctuated by LED daytime running lights. Full LED headlights are optional.

The roofline tapers smoothly into the hatch and designers have come up with wide tail-lights that spread across into the hatch lid. A built-in spoiler runs the width of the latter and pops up automatically above 130km/h, before dropping back down at speeds below 80km/h.

Milano leather trim is standard on all A7s, as is a reversing camera, sunroof, keyless entry and starting and Xenon headlights.

Audi Australia says it expects to sell between 150 and 200 A7s in its first 12 months and says it is an important player - alongside the A6 and A8 - in increasing Audi’s share of the image-building large-car segments.