Sportback hot enough to burn petrolheads

Since that original RS6, the company's RS – for Renn Sport or sporting racing – range has grown and matured, offering ballistic performance in a variety of body styles.

Now there's the new RS7, which shares the same turbocharged V8 powerplant as the current RS6 estate but in a slippier Sportback body style.

The look is of a high performance coupe, but strictly speaking it doesn't fall into that category because it has four doors. There are clues to its potential, of course, such as the big front air intakes, oversized alloys (21 inches on the test car, 20 inch are standard) and extra aerodynamic touches.

But it's still a bit of a 'Q car' because they don't tell you that this car's twin turbo, eight cylinder, four litre engine has a whopping 560Ps (552bhp) of power and no less than 700Nm of torque.

Not surprising then that it is capable of tackling the 0 to 62mph sprint in under four seconds, and – depending on your chosen options (and the size of your wallet) a potential top speed ranging from 155 to 189mph.

That puts it within a gasp of the iconic R8, and while it doesn't have the same jaw-dropping supercar looks it does have four seats and a family sized boot, making it appeal to a different type of buyer.

The basic price is £82,010, but if you want to reach the holy grail of performance or simply give it even more sporting looks you can do that at a price.

The 'dynamic plus package' for example replaces the standard air suspension with conventional dampers and steel springs plus a hydraulic system to reduce pitch and roll. You also get superb carbon-ceramic brakes and uprated steering. It means the limited top speed goes up to the maximum 189 if you want to spend £10,725.

The carbon styling package which includes, among other things, sprucing up the huge air intake ducts with the panels stamped with 'quattro' badges, is £4,250.

Rather surprisingly the sports exhaust is an 'extra', too, at £1,000 but you really would miss it. The deep growl of the V8 under acceleration, or when the eight-speed auto box changes up or down, is like a musical accompaniment.

The potential of this car is awesome, even perhaps a little intimidating to some, but there's lots of Audi's vorsprung durch technik which tames the beast and turns it into a well-trained thoroughbred.

Some drivers who see themselves as purists like the feel of rear wheel drive in a powerful car, but others are not so sure in wintry weather and prefer the reassurance of a system like Audi's legendary Quattro all-wheel drive for added grip to put the power down safely.

It channels power to all four wheels using torque vectoring and an electronically controlled limited slip differential, making adjustments in milliseconds to give you the best possible traction in any conditions.

The car has Audi's 'drive select' system with comfort, auto and dynamic settings which adjust the responses of the transmission, suspension, steering and even the exhaust note according to conditions and your preferences. It means, for example, that the car is more relaxing, more civilised, to drive in traffic than high performance cars once were.

In 'comfort' mode in particular the RS7 is cossetting to drive or ride in, and smoothes out the surfaces of some our typically British 'b' roads in a way which would have been unthinkable in a performance car, or even a hot hatch, just a few years ago.

The steering is taut and positive whichever mode you're in, but it's impossible to say too much about the car's handling: the only way to fully explore that would be on track.

The engine has a neat trick too. When the engine isn't under load it shuts down four of the eight cylinders to save fuel. That means potential economy of almost 29mpg, impressive for a car in this class, and CO2 emissions of 229g/km.

All those 700 Newtonmetres of torque are on hand at just 1,750rpm. Combined with the rapidly reacting eight speed transmission it means that for most of the time the rev counter is showing around 1,500rpm – but a touch on the throttle means virtually instantly, eye-popping acceleration.

The RS7, apart from its unique styling touches, comes with home comforts such as heated, electrically adjustable sports seats, a comprehensive media system, SatNav, a premium 14-speaker stereo, parking sensors, sunroof and four-zone climate control.

But a particularly useful feature in a car like this is the jet fighter style head-up display, which projects your current speed onto the windscreen in front of the driver's eyes – a genuine boon to keeping you safe and legal.

By John Griffiths