Used Audi S8 2015-2017 review

Fundamentally the drivetrain remains the same. The engine’s mighty output is distributed to all four wheels through an eight-speed Tiptronic automatic gearbox. From there, and under normal circumstances, a central differential sends 40 percent of the drive to the front axle and 60 percent to the rear - where it’s divided once more by an electronic limited-slip diff. But, if needs be, up to 100 percent of the drive can go to the rear.

As the standard S8 has been known to cook its brakes when driven hard, we'd opt for the Dynamic Pack. It includes fade-resisting 19in carbon-ceramic brake discs and swaps the 155mph limiter for one that pegs things at 189mph instead.

The result is brutal acceleration accompanied by a gloriously deep baritone rumble from the quad tailpipes – which for S8 Plus spotters, are painted black instead of the standard car's chrome.

One Audi engineer told me this car should crack 200mph with no restrictor, and they’d only limited it because of the tyres - or perhaps to spare the blushes of the Bentley Flying Spur? Judging by the phenomenal rate at which the S8 Plus keeps pulling, even when it’s already at mammoth speeds on a de-restricted autobahn, I feel no reason to doubt the claim.

In these situations Dynamic mode works best. It stiffens the suspension and helps keep the big Audi planted even as you motor past trundling HGVs. It also weights up the Dynamic Steering, which otherwise feels a bit insubstantial, albeit quick.

The test route didn’t take in many twisty roads, but preliminary analysis indicates that for its size, the S8 is pretty wieldy. Traction is epic and it manages to resist rolling much on its uprated air springs, even as you pile on more cornering speeds and lateral g.

However, all this agility isn’t at the expense of the S8’s other role as a cosseting chariot for the well-heeled. Yes, it has smoother-riding peers, but switch to the softer Comfort mode and it floats along without much fuss, even on the standard 21in rims.

Whether it’s because of the trick noise-cancelling software or layers of old-school sound deadening, the road and wind noise never startle, even at very startling three-figure speeds.