The A8 is expensive even if you don’t get carried away with the seemingly endless options list. It’s also not going to be cheap to run, even though Audi claims its fuel consumption is 19 percent better than the outgoing model’s: diesel or not, you don’t give a car the ability to accelerate two tonnes of metal to 60mph in five seconds without paying a price at the pumps.
We put the 4.2 TDI through its paces on our test route and managed 26.3mpg overall, which is likely to be representative of what can be expected over a tankful of varied driving conditions and about 10mpg shy of Audi’s claimed average. We'd expect that sort of margin from the official economy figures to be true across all engine configurations.
Depreciation is never kind to this class of car. However, the Audi A8 is forecast to be hit harder than its immediate rivals. In its first year alone, a 4.2 TDI SE Exec will lose a shocking 51 percent of its list price. That’s better than any of the petrol cars, but the smaller diesel will fare much better. It should also improve your economy by around 6mpg, while emissions are usefully lower at 174g/km for the short-wheelbase car.