Audi A6 Avant
With the saloon on sale for just a few months, Audi has completed the A6 range with the addition of Avant estate versions due for launch in November, with the emphasis on being larger but lighter.

Audi expect the seventh generation A6 Avant to go right back to the top of the class, but can it split the BMW and Mercedes rivals? I headed to Cheltenham for an early UK drive.
Key in making the A6 Avant lighter is the use of aluminium components, which make up roughly 20 per cent of the body. The result is that the gross weight has been reduced by as much as 70 kilograms, depending on the engine, compared with the outgoing car.

For example, the A6 2.0TDi weighs just 1,640kg, 15 per cent less than its all-steel equivalent.

Audi A6 Avant
The emphasis might be on being larger, but the A6 has 565 litres of load space. This might be five litres more than the BMW 5-Series, but way shorter than the current E-Class's 1,950 litres. Fold the rear seat down and the A6's boot space increases to 1,680, but this is still less than you'd get in the BMW at 1,760.

A choice of four engines are available for the Avant in the UK: one petrol and three diesels. Diesel engines start with the 175bhp 2.0-litre TDi diesel, moves up to 201 and 242bhp versions of the 3.0TDi and the most powerful engine, the 296bhp 3.0-litre TFSI petrol.

Early next year, a fourth diesel engine will be added, the all-new twin-turbo 3.0-litre TDi diesel.

All of these engines feature green technology including a start-stop system, energy recuperation and the innovative thermal management system, that quickly brings the coolant and motor oil up to temperature.

The cleverest feature of the most aerodynamic range in its class is the boot. This can be opened automatically simply by 'gesturing' Basil Fawlty-style with a foot, to two sensors under the rear bumper, if the optional advance key feature is added.

Audi A6 Avant
SE and S-Line trims are available, with a high level of standard equipment including alloy wheels, leather trim and front and rear parking sensors. Options include, a head up display, on-line and Google Earth mapping with the MMI navigation, plus system and Bluetooth internet connection.

I had the chance to drive all the engines in the A6 Avant range; least impressive was the lazy 201bhp 3.0TDi which seemed slow to respond. Both the 3.0-litre petrol and the 242bhp diesel versions are quick but lack involvment.

My favourite, like the saloon, has to be the entry-level 175bhp 2.0 TDi. With less weight, front wheel drive, a slick six-speed manual gearbox and light, acurate steering, it was the most satisfying of all the A6 Avants that I drove.

It might be bit of a chugger compared with the refinement of the bigger petrol and diesels engines, but there's enough performance, it has CO2 emissions of 132g/km and is capable of 56.5mpg on the Combined cyle, which is impressive enough to make it my pick of the Avant range.