DRIVING the new Audi A6 is taking a trip in the light fantastic.

Building on experiences gained with the Audi TT, R8, A8, A7 and previous generation A6, the new car uses the latest composite aluminium and super-strength steel techniques to bring it in at 15 per cent less weight than an all-steel equivalent.

Major body panels, many suspension components and axles are aluminium, for instance.

The weight saved is typically equivalent to that of two adults and despite its size the A6 2.0 TDI takes its fight to rivals at a trim 1,575kg, which means with the latest high efficiency petrol and diesel engines under the bonnet and low friction transmission bolted onto them, the fuel efficiency and tax beating emissions are very good.

With a longer wheelbase and wider track, the lightweight yet roomier design also endows the seventh-generation A6 with very good responses and agility, even from the lowest powered engine, reduces sources of noise and puts it on a performance-par with some rivals using bigger and less efficient powertrains.

There is a choice of 177PS 2.0 TDI, 204PS 3.0 TDI, 245PS 3.0 TDI diesels and 300PS 3.0 TFSI petrol engines which are fitted with stop-start technology, recuperative braking technology, electro-mechanical steering, transmission fluid warming.

Together these combine to give yield up to 19 per cent better economy than the previous generation A6 launched in 2004.

Depending on model there are manual six-speed or automatic seven and eight-speed transmissions and eventually there will also be a petrol-hybrid version.

Later this year we will see Avant estate derivatives join the new saloons in SE or S-line trim versions, two or all-wheel-drive, with standard, sport, quattro or air suspension available and the new ten model range is priced from £30,145 to £41,640 on the road.

With three-quarters of Audi A6 buyers using them for business, the new version offers substantial savings on benefit in kind, up to £862 annually in some cases, and the latest series is projected to have strong residuals between 37 and 40 per cent which help with overall leasing rates and combined running costs, elements which will also help private buyers.

Budgeted service and extended warranty programmes are available.

Audi expects to sell just under 10,000 A6 models in a full year, with 75 per cent being the 2.0 TDI and 60 per cent will be the entry level SE specification with six-speed manual gearbox.

The specification includes standard leather seats, multi-media interface for audio, Bluetooth phone and SD-card based navigation, dual zone climate control and heated powered mirrors, while the S-line trim has bigger wheels and lowered suspension, electric front seats and xenon lights among its changes.

There is an enormous range of additional equipment which can be added by individual customers including head-up essential information display, park assist, night vision, lane assist, adaptive lights and upgraded sound and navigation systems. It is even possible to choose integration with Google Earth down-loadable navigation and you can simultaneously run five PCs off the car's on-board computer.

The predicted best selling front-wheel-drive Audi A6 2.0 TDI SE manual with its low CO2 emissions of 129g/km is what the designers intended it to be, a very good introduction to the new range.

Don't be fooled or put off by the seemingly modest engine in a large car, it pulls very well from rest or when overtaking and cruises with remarkable composure and economy.

I managed to return an indicated 50mpg overall on a short test drive and a more enthusiastic companion saw 48.9mpg.

It is a quiet engine when gobbling up motorway miles or sweeping main roads, only producing a more noticeable note pressing on in lower ratios with higher revolutions, and wind noise is extremely low.

You can, however, hear the suspension and road noise from tyres and at times the standard suspension was surprisingly firm over scarred A and B class road surfaces, and some potholes taken at moderate speed notably jarred the car.

Generally, the ride was good with little or no body roll, well controlled damping and the interior is very roomy in all directions. The boot is also big and easy to load.

Visibility was very good all round with slim pillars to the roof and low waistline.

The new Audi A6 will delight existing owners of brand products who want to trade up or down for whatever reason and it represents a very strong case for choosing over closer rivals.

Perhaps the strongest case is what few consider until they are stuck, the Audi A6 is available with four-wheel-drive and as two-thirds of UK days are wet or snowy, it could keep you mobile and safer than anything else in its class.