WHAT has a blistering 3.9 second 0-62mph sprint time and a possible top speed of 189mph but will still seat five in comfort and has enough room in the back to take an old fridge freezer to the tip?

I'm talking about the stunning new Audi RS6 Avant which makes its debut in the UK in July - this rocketing estate is faster off the mark than a Porsche 911.

The previous RS6 used a 5.2-litre V10 Lamborghini engine and the new version gets a four-litre bi-turbo V8 which produces 552bhp but is actually quicker thanks to weight reduction of around 100 kilos and a new eight-speed tiptronic gearbox.

It's also 30 per cent lighter on fuel and Audi claims you can now get 28.8mpg from the beast on a combined run, although the power offered by this German flying machine will probably mean owners with a heavy right foot will get much less. But, if you can afford the £77,000 price tag, fuel saving probably won't be a top priority.

Helping to save fuel is the stop-start system on the new RS, plus cylinder-on-demand, which shuts down four of the eight cylinders when he RS6 is cruising until you accelerate hard, and believe me, you don't notice the change.

The 189mph is possible if you opt for the Dynamic Plus pack but without it the RS6 is limited to a "mere" 155mph, which I think is fast enough. I chickened out at 130mph on unrestricted German autobahns during the launch.

But even at that speed this reasonably big estate glides along, perfectly planted with very little road or wind noise and with superb braking power for the 20-inch wheels as a back-up while the four-wheel quattro system offers secure cornering on ordinary roads.

Steering is pin sharp and you can throw it into bends with confidence with very little body roll.

Acceleration is blisteringly quick and smooth which makes overtaking easy and safer than your normal car.

It's also very civilised around town despite a pretty stiff suspension set-up and it soaks up most holes and bumps without to much jarring.

As well as being fun to drive the RS6 is a comfortable motor with superb body-hugging, electrically adjustable front seats in leather and it has plenty of head and legroom for rear seat passengers.

The load space is good, offering 565 litres or 1,680 litres with the seats folded and you can specify a hands-free opening system as an option.

Audi interiors are always of high quality and the new RS is no exception with nice trim and touches of brushed chrome features giving it a touch of class.

It has a new flat-bottomed three-spoke multifunction sports steering wheel with gear shift paddles if you prefer to use them over the tiptronic auto, it also has a full navigation system on an eight-inch screen, a Bose 14-speaker sound system, parking aids and much more.

Body styling is sporty, without being over the top. But it has a distinctive appearance, with touches of aluminium on the body, including the wing mirrors plus a black honeycomb grille up front.

Bumpers and wheel arches are flared and the RS6 has a large roof spoiler and rails and twin exhausts which emit a great sound both inside and out.

An optional sports exhaust system will be available for even louder amplification if you really want to turn heads.

The RS6 is a lot of cash but for a practical car with credentials like a supercar the RS6 Avant is in a leauge of its own.