It’s the ultimate version of the Audi A8, itself a byword in understated luxury.

The new S8 plus, with an engine closely related to that of the Bentley Continental, pumps out more than 600 horsepower and can clock 189mph – and more.

 
It is best ignore the figures and stats before you slide behind the beautifully crafted wheel of the Audi S8 plus.

Because they can be somewhat daunting – the twin turbocharged V8 whacks out up to 553lb ft of torque in overboost. It takes a mere 3.8 seconds to hurtle to 62mph, and without any speed limiter the five seat luxury saloon would be good for more than 200mph.

There are those, and I can appreciate this, who would grumble that the steering fails to relate strongly enough with the driver in the way a Jaguar, Porsche or Ferrari might. But Audi argue, probably justly, that their customers like it that way.

Of course, Audi is a responsible company and most owners who fork out the near £100k required for one of these super saloons want to carry on enjoying living their sumptuous lives.

So a standard – if that’s the best word – S8 plus comes with its terminal velocity electronically restricted to 155mph, as do the majority of German exotica under a voluntary agreement. But buyers can elect for the ‘dynamic package’ which raises the bar to a more generous but still controlled 189mph.

But speed and power are just a small part of the story. Fire up the 4.0litre V8, tap the accelerator and you get the most superb muffled roar from the exhausts. It’s a sound that leaves the driver in no doubt about what’s to come.

While Audi used a V10 for the legendary R8 two-seater, a 4.0litre biturbo V8 not totally dissimilar to that in the Bentley Continental was their engine of choice for the S8 flagship.

From the outside, ‘my’ S8 Plus was mean and brutal in metallic black (sorry photos of this car were unavailable), with huge 21inch 9J black alloy wheels that filled those arches a treat. The rear view – an angle most other road users will probably view the car from – is similarly impressive with two large black, high gloss oval tailpipes emerging from the left and right of the rear valance. Darkened tail lights and a rear lip spoiler complete the image.

Inside, 22-way electrically adjustable sports seats in black leather with contrasting stitching and matching headlining remind you that this is no normal saloon. Super-thin strip lighting illuminates the areas above the side windows and lends a warmth to the passenger compartment. Black piano paint trims the gear selector lever of the eight-speed tiptronic system.

With quattro four wheel drive and sports differential to apportion the fulsome power output, the S8 plus merely goes where it is pointed … very quickly. There’s a slight shimmy on a moist road as the power is transmitted, then it’s drama-free progress, set to a harmonious V8 symphony.

There are those, and I can appreciate this, who would grumble that the steering fails to relate strongly enough with the driver in the way a Jaguar, Porsche or Ferrari might. But Audi argue, probably justly, that their customers like it that way.

Cornering levels are prodigious with neither understeer nor oversteer being apparent at normal speeds. The ride is firm without being harsh and the suspension has sufficient movement to smooth out all but the worst road imperfections.

Stopping is looked after by fade-resistant carbon-fibre reinforced ceramic brakes. A nice finishing touch are the anthracite grey callipers bearing the Audi logo.

Sometimes, ramping up the power serves only to expose weaknesses in an otherwise acceptable design. But in the case of the S8 plus, the changes have lifted the prestige saloon into an area occupied by legendary machinery.