The Avant's exterior certainly pulls no punches when it comes to expressing power. The bulging wheel-arches are filled with huge alloys and tyres that any supercar would be proud of. Massive, 20-inch alloys are standard but 21-inch alloys are available options. When you see the machine at speed, the five-seat RS6 looks like it is glued to the road. Motors went to Munich to test the RS6 on some derestricted roads that nature intended for it.

Weighing around two tonnes, the five-seat Avant effortlessly cruised for kilometre after kilometre at speeds in and around the electronically-limited 250km/h (155mph). This rock-solid ability to travel, handle and stop from truly high speed is a testament to how well-engineered the Audi is. The third-generation Audi RS6 is sublime and improved in every way - even the loss of two cylinders (from 10 to eight) isn't felt.

The last '2008' RS6 was fitted with a Lamborghini-sourced V10. Power now comes from a beautiful Twin-Turbo V8 petrol engine that produces 560hp and a whopping 700nm of torque. 0-100km/h takes a supercars quick 3.9 seconds and top speed (derestricted with the optional 'performance pack') is 305km/h (189mph)! The Quattro all-wheel drive system delivers so much traction it performs and grips like a demented squirrel racing up a tree.

New fuel saving technologies (as if buyers are going to be concerned about this), like stop/start and 'cylinder on demand', reduce fuel consumption to an average of 9.8L/100km (28.8mpg). This represents a 30% improvement on the 2008 model. To get this huge amount of power to the four wheels, Audi has fitted an eight-speed Tiptronic automatic gearbox (with paddle shifts). The gear ratio has been shortened and top gear is now longer.

RS6 rides on specially-tuned adaptive air suspension. Audi 'Drive Select' is standard and this allows the driver to choose from different driving modes. Individual (personalised) worked best for me as I could tune it. If you want a relaxed drive, just leave the Drive Select in 'Auto'. A dynamic pack - adding ceramic brakes and dynamic steering (that has very fast gearing) - turns the standard car into a truly awesome performer. On the road the estate car is capable of being driven slowly with little effort. The big, versatile machine is incredibly functional, with a massive boot.

I have often quoted the previous-generation BMW M5 Touring as the ultimate family fantasy car, but the crown now moves to Audi with the outrageously capable and sure-footed RS6. The sound it makes when accelerating hard is spine-tinglingly good thanks to modified rear exhaust baffles. There is good news for fans of sportier Audis as the German firm is set to make RS versions available sooner in each model's life cycle.

RS6 pricing starts at €139,500. Expect to pay in excess of €10,000 for the additional dynamic bits from the options list. But true enthusiasts who can access a racetrack or German autobahn should invest in the ceramic brakes etc to get the best out of the stunning machine.

The RS6 is the ultimate estate car!

Michael Sheridan