Audi A8L 4.2 TDI

So, it’s no surprise that the 2008 model-year facelift has largely left the looks alone. The A8 in our pictures is a current 2007 version, but order one now and your new saloon will arrive with a reworked grille, fresh front and rear lights, plus a different wing mirror design.

Standard equipment has been changed, too, although the interior remains mostly unaltered. While it isn’t as modern as some in the class, it feels expensive without being flash. And as with the Lexus, it’s very hard to fault the quality and finish, although the metal switches and use of wood give the A8 a higher-quality air.

The controls are logical and user-friendly, while our only criticism of the driving position is that the seats are rather firm. This gripe can also be levelled at the rear chairs, but at 130mm longer than the standard A8, this long-wheelbase version is still a very relaxing car to travel in. Noise from the diesel engine has been well subdued – recorded from the back seat, its reading at idle was 39dB, which was identical to the Lexus’s.

The Audi is louder than the LS at 30mph and 70mph – at 55dB and 65dB respectively – but while there is an element of gruffness to the V8 diesel under acceleration, it’s as smooth and quiet as most petrols. Only the Lexus’s exceptional refinement makes the A8 seem even vaguely noisy.

Despite their completely different approach to technology and engineering, the two cars are very evenly matched in terms of performance. The Audi’s V8 diesel delivers effortless punch from 1,500rpm, with the A8’s aluminium construction helping to keep the weight below two tonnes, and ensuring surging acceleration times. The twin-turbocharged common-rail diesel provides a great mix of speed and flexibility, and it’s a mystery to us why BMW and Mercedes don’t follow suit and bring their V8 diesel luxury models to Britain.

Complete with steering wheel paddles (a feature that highlights the A8’s more sporting orientation), the Audi’s Tiptronic gearbox allows better manual control than the Lexus, although upshifts are slightly smoother in the Japanese car.

While there’s a silkiness to the Lexus’s driving manners that the Audi simply can’t match, the A8 does try to include the driver, rather than isolate them. On an A-road, this gives the German saloon a substantial advantage. The steering is more in touch with the road, roll is better controlled and, as a result, the 4.2 TDI instils far more confidence and feels less cumbersome.

Ride quality remains good, too. The A8 benefits from adaptive air-suspension, which allows you to select from four settings via the MMI system. As with the Lexus set-up, it continuously regulates damping, and although slightly firmer than its rival, the A8 is still effortlessly luxurious. It lacks the ultimate cushioning and mechanical isolation of the hybrid, but its fluent handling makes it a very pleasant car to drive.

The Audi doesn’t come close to matching the Lexus’s standard kit tally. Yet it is £18,680 cheaper, which means you’ve got cash to spare to indulge yourself in the options list. And if you still wanted to drive a hybrid, you could afford to buy a Toyota Prius and have change left over.

Details

Price: £64,965
Model tested: Audi A8L 4.2 TDI
Chart position: 1
WHY: With its peerless image and strong eight-cylinder diesel engine, the big Audi is a fine luxury car.

Economy

The Audi averaged a far more frugal 31.5mpg, proving that the A8’s light weight and diesel power are a better formula for real-world economy. This means a huge 624-mile range.

Residuals

The A8 doesn’t fare as well in percentage terms, retaining 38.3 per cent of its new value. But the lower price means it loses £40,084 – over £10,000 less than the Lexus.

Servicing

Audi has more dealers, but they don’t look after owners as well as Lexus’s – they came 16th out of 32 in Driver Power 2007. And three services on the A8 cost £1,870.

Tax

Factor in the three per cent surcharge for diesels, and the 249g/km CO2 figure puts the A8 in the top tax bracket. Higher-band owners pay £9,095 a year.