It is just difficult to see how it’s worth it. Yes, the W12 will hit 62mph from rest in 5.2 rather than the 6.4sec of the 4.2, but is this really so important in such a car? Both will reach the same electronically limited 155mph, while the W12 slurps unleaded at 20.5mpg combined, compared to the still scarcely frugal 23.5mpg of the 4.2-litre car.
But even this is not really the point. What we found hardest to accept was the fact that the 444bhp W12, far from being the paragon of refinement you might expect from such a flagship limo, is actually more intrusive than the V8s of lesser A8s. We don’t remember significant engine noise at a 90mph cruise in V8 A8s but in the W12, it’s there all the time.
Audi’s engineers may or may not be able to produce sound readings to prove the W12 is quieter at such speeds than its eights, but on a qualitative assessment, to these ears, the V8 is the smoother, sweeter engine.
Our final gripe concerns ZF’s six-speed automatic gearbox, a unit we had presumed, until now, could do no wrong. We’ve driven Jaguars, BMs and Bentleys (not to mention other A8s) equipped with this gearbox and been unable to find fault with it. But in the W12 A8, or at least in the car we drove, it inexplicably held onto gears longer than we wanted, again not something you want in such a car.
Having now trashed this A8, allow us to put it into some context. We believe the A8 range is still the next best thing to that of the S-Class Mercedes, so we are still talking relative merit.
These cars are limousines and the more you pay for them, the more limousine-like they should be. So if that extra 17 grand brought new levels of ride and refinement to the A8 instead of dubious performance, we’d no doubt feel rather differently about it. But it doesn’t. The ride, so far as we could tell on the smooth-ish German roads in and around Ingolstadt where we drove the car, is no better in the front or the back and yet refinement appears to have taken a backward step.
Of course, the A8’s many other talents have survived intact – the brilliant driving environment, superb MMI infotainment system and beautiful cabin being chief among them. The 130mm stretch in the wheelbase has also been effortlessly integrated into the design without spoiling the proportions. In the back, legroom is wonderful, even for a 6ft 4in adult sitting behind a 6ft 4in adult.
But you can enjoy all the advantages of the long wheelbase without having to spend over 75 grand – it’s a £3370 option on all A8s save, curiously, the 3.7-litre V8.
In short, the A8 L 6.0 is the most disappointing of the A8s we’ve driven. Turning it from an inspired large saloon into a limousine pushes the car in a direction in which it does not care to travel. The fundamental and well-documented limitations of the A8’s merely reasonable ride do not suit the limo treatment while, in this application, the W12, for all its fine specification and impressive power, is neither sufficiently smooth nor special.
And while there are certainly those in the Autocar office who find the grille perfectly agreeable, the best thing I can say about it is that, mercifully, it’s not going to be a feature of any other A8 – for the time being at least. Its role, then, is as gold to a Rolex – and more evidence to suggest that money and taste are often inversely proportional.
None of this will worry Audi. This is a car it had to build to match the equivalents from Mercedes and BMW and it’s entirely realistic about its chances in the showroom. Orders for UK cars are already being taken right now and it will be happy if it receives two a month.
In the meantime, Audi’s reputation as the luxury car manufacturer with its star most firmly in the ascendant continues to be bolstered by the other less-expensive A8s, like the quite excellent 4.0 TDi, the first luxury car that comes close to rivalling and, in areas, bettering the mighty S-class. It’s just a pity that such an otherwise capable range has been finished off with a stumble, not a flourish.