USED Audi A8 Saloon (03 - 10)

It’s a huge saloon that has much to offer anyone in search of a luxury motor that isn’t a BMW, Mercedes or Jaguar. The innovative aluminium body means it’s lighter than many rivals, helping performance and economy. Four-wheel drive is fitted to most, as is air suspension, offering a choice between four settings.

The cabin is vast throughout, while the boot offers more than ample space. The long-wheelbase version is rare but brings even more space in the rear seats. It’s a very well-built car and the quality of the materials used matches, and sometimes beats, the competition's.

Even the cheapest models drive beautifully, feeling smaller than they look, while the high-performance models are seriously quick. The diesels are state-of-the-art but the smaller petrols are accomplished, too. There simply isn't any road noise and, while you’ll hear some wind noise, it's completely silent otherwise.

The 3.0 diesel model makes most sense. Not only does it promise up to 32mpg - a good return for a big, four-wheel-drive car - but it’s one of the cheaper models to buy. If that’s not enough to persuade you, it also loses value more slowly than other A8s. Otherwise, the smallest petrol engine, the 3.2 V6, makes a fair fist of hauling the car quickly, while keeping buying and owning costs to sensible levels.

Whichever model you look at, you'll have plenty of kit, with sat-nav, leather seats and keyless entry on all. Parking sensors ease the worry of parking in town; they’re a real boon, particularly on the long-wheelbase version.

Only the 3.0 diesel and 3.2 petrol versions keep costs at a semi-sensible level. As for the rest, they are only for the seriously wealthy.

As ever on an A8, stiff depreciation is an issue, but it's good news for a used car buyer. The first owner suffers the worst hit from new, leaving the second owner to pick up a relatively cheap executive car.

There's no escaping the high running costs, though. Insurance is group 18 for the smaller engines, group 20 for the rest. Be aware, though, that some companies won’t touch the car because of its aluminium body - which is complex and expensive to repair - while others will load the premium. Servicing is also best left to Audi dealers who specialise in the A8, which will make it dear.

Fuel economy ranges from the excellent 32mpg from the 3.0 diesel to 28mpg for the 3.2 petrol and 4.2 diesel, and 20mpg from the 6.0.

Older A8s aren’t dependable, according to the What Car? Reliability Survey, while the average cost of repairs is well over £500. The A8 looks built to last, but the complicated air suspension threatens horrendous bills if it develops faults, so check it out thoroughly before you part with any cash.

Audi engines are proven and reliable, but the gearboxes and clutches will need overhauling once the miles mount up. We’d worry that those complicated electrics might give trouble, too.

Despite the cost, correct servicing is of paramount importance, while a full set of main dealer stamps in the service books is essential to maintain the car’s resale value. Skimping on proper servicing now could cost you in the future.

The cost of fixing that aluminium body is an even greater concern. Regular crash repairers won’t touch it, leaving just a few specialists to tackle the work - and charge you plenty for the privilege.

Four-wheel-drive (quattro) models should have all four tyres replaced at once to maintain traction and handling - a full set can easily cost £1000.