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Audi sells about 1,000 A8 saloons every year in the UK - something that's easy to forget when all the attention is on the new BMW 7 Series and the class-leading Mercedes S-Class. The Audi's 3.0-litre TDI makes up the bulk of sales, but an intriguing 10 per cent are accounted for by the 513bhp S8 super saloon.
With a new A8 not due until 2017, Audi has upped its game by introducing the fastest accelerating and most powerful S model ever. Driven here for the first time, the S8 Plus is about as close as we’ll get to an RS8 this decade, but with 597bhp a tweaked chassis and optional carbon ceramic brakes, we’re not complaining.
The S8 Plus is a brute: a European muscle car aimed squarely at the Mercedes-AMG S 63. It commands a premium of £16,315 over the current S8 and will be sold alongside it with first deliveries in the spring.
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Along with the 84bhp boost over the standard car, it also gets an extra 100Nm of torque (up to 750Nm). That’s not only more than a diesel-powered Q7, but a whopping 160Nm over and above what’s available in the new R8 V10.
That means 0-62mph takes just 3.8 seconds (versus 4.1 seconds in the standard S8), and it feels every bit as fast on the road as it seems on paper.
Acceleration from a standstill is relentless. If you’ve got the means to do so, it’ll surge straight through the national speed limit, past the standard car’s 155mph limiter and on towards 200mph, keeping you pinned in your seat all the way. Where some supercars would tail off, the S8 just keeps on pulling.
In fact, even with the optional Dynamic Package selected, Audi engineers have had to restrict the S8’s top speed to 189mph due to tyre and drivetrain restraints. Peak power is delivered from 6,100rpm, but all 750Nm of torque comes in on overboost from just 2,500rpm.
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While it’s relatively sedate in Comfort, switch through the driving modes to Dynamic and it sounds like a hurricane at full chat. Plant the throttle and the active exhaust opens wide to unearth a deep V8 bellow as you pass slower moving traffic with ease.
Despite all this, it’s magnificently quiet at normal motorway speeds thanks to clever sound cancellation technology. Yes, if you regularly steam down the autobahn at 150mph you’ll notice a bit of tyre roar and some wind whistle around the door mirrors, but at 70mph it’s surprisingly compliant. As a result – and just like the rest of the A8 range – it should prove enormously easy to live with day-to-day.
While the S8 Plus may accelerate as fast as a previous-generation Audi R8 V10, we wouldn't expect it to handle like one. It’s no Porsche Panamera, but there’s very little body roll and turn-in is sharp. The steering could do with a little more weight and feel, but it belies its size and grip is good thanks to the all-wheel drive system.
The gearbox is a single clutch eight-speed tiptronic, and while it isn’t super-smooth, it’ll change quickly in either direction with a pull of the steering wheel-mounted paddles. There’s no Audi TT-style parp on full-throttle upshifts, but it’ll allow the V8 to burble on the overrun when you lift off the gas.
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But that’s not all. Cylinder-on-Demand trickery should mean it’s one of the more affordable super saloons to run, too. Ok, so 28.2mpg and 231g/km is hardly frugal – but it’s only 1.2mpg down on the standard car and that’s despite the significant power hike. A Jaguar XJR falls someway short of the S8 Plus, even though it is significantly down on power.
Standard kit is good too, with Matrix LED headlights, Bose stereo, Nappa leather seats and double glazed rear windows all included. The Plus is distinguishable by its high-gloss detailing, darkened rear light clusters and it undercuts its main rival – the Mercedes-AMG S 63 by a full £23,990. For that, you could buy a well-specced Audi A3 TDI for less exuberant trips to the shops.
- Model: Audi S8 Plus
- Price: £97,700
- Engine: 4.0-litre V8 twin-turbo
- Power: 597bhp/750Nm
- Transmission: Eight-speed auto, four-wheel drive
- 0-62mph: 3.8 seconds
- Top speed: 189mph (with Dynamic Package)
- Economy/CO2: 28.2mpg/231 g/km
- On sale: Now