Weight is the enemy of the luxury high performance saloon. That's one of the main reasons why Audi went to all the trouble of ditching the previous S8 model's Lamborghini-sourced V10 for this MK3 S8 model's lighter and more efficient twin turbo V8. It certainly sits in a lighter, more efficient 'Audi Space Frame' body, made almost entirely of aluminum, with only the B-pillars constructed from ultra high-strength steel. This bodywork itself weighs just 231kgs - about 100kgs less than steel-bodied rivals. Which means that this Audi can carry around the kind of heavy quattro 4WD system its rivals lack, yet still undercut many of them on the scales.
And the look? Is it classier than the competition? Many will think so. We can't completely put our finger on what it is but there's something about this car that makes you feel a better, more tasteful and more accomplished person simply by being in its company. There are showier, faster rivals but none has uber-coolness down to such a fine art as this S8. A lot of it's in the detail. Audi S cars have a reputation for styling subtlety and the S8 is no exception.
The single frame platinum grey front grille with its chromed eight double bars is a work of art, as are the aluminum-ribbed side air intakes. There's more aluminum-style trim on the door mirror (a classic S-brand touch), plus gorgeous 20-inch alloy wheels, the subtle integrated boot spoiler and the four chromed tail pipes surrounded by a redesigned rear apron. Most won't know what has just blown by and is disappearing into the distance.
The interior is similarly restrained but impressive. Everywhere you look, there's a beautiful blend of craftsmanship and technology. As you enter in admiring the illuminated door sill trims, the alcantara headlining and the aluminum-trimmed pedals, the display of the driver information system and a central MMI infotainment monitor that glides out of the dash both greet you with special S8 screens.
There's full leather of course and at the front, multi-way power-adjustable comfort sports seats designed exclusively for this model. The three-spoke S quattro steering wheel has colour-contrasting stitching and a set of aluminum-look shift paddles just behind it. Beyond them, you view a set of bespoke instruments, grey dials with white needles, a theme repeated on the classic analogue clock. And special mention must go to the gorgeous aeronautical gear lever than makes you feel like you're bringing a 747 in to land. Brilliant.
What about luggage space? Well, power open the electrically operated boot lid and you'll find that it hasn't increased very much over what was offered by the previous generation version, despite the fact that this car is 75mm longer, 55mm wider and 16mm taller than its predecessor. As a result, there's 510-litres on offer - only average for this class of car. Still to be fair, that's more than you get in a rival Porsche Panamera and given that it's easily enough for, say, four golf bags, we think most owners will be quite satisfied.
Perhaps, like us, they'll be expecting all that extra size to have benefitted those seated in the rear. If it has, then to be honest, seated back here, you really wouldn't know it, with overall standards of passenger room pretty much as before, even though the cabin is now nearly two metres wide. But then how often do cars of this kind travel with three adults across the back seat? Boadroom buyers rightly place far more importance on the way their carriages can carry four and this one does so with measured elegance, beautiful ambient lighting and hand-sanded and varnished wood panels reminding you how much you've paid.
Most S8 owners we surveyed were very happy with their cars but inevitably, there were a few issues reported. We've come across air suspension issues. And one owner had problems with the turbos. Tyres won't be cheap, so check the supplied rubber carefully. Audi's quattro 4x4 system should prove reliable and the engines have all been used extensively in other Audi models so there should be little cause for concern there. Look out for interior scuffs and alloy wheel scrapes. Otherwise, you shouldn't have much to fear, even from a high mileage example.
(approx based on a 2014 S8 - Ex Vat) An air filter costs around £58, an oil filter costs in the £10 to £15 bracket and a fuel filter costs in the £17 to £22 bracket. Front brake pads sit in the £50 to £70 bracket for a set, while rear brake pads cost around £36 to £46 for a set. Brake discs cost around £50-£78, though we also found pricier branded ones in the £138-£250 bracket. You'll pay around £140 for a water pump and in the £232 bracket for a headlamp bulb. Wiper blades cost in the £10 to £19 bracket. The wing mirror glass is priced in the £30 to £35 bracket.
It's easy to quote power figures with a big performance saloon like this but the massive weight that some of these models have to lug around can often make such figures often somewhat irrelevant. The acid test of a car's potency is its power to weight ratio and it's rather surprising to note that, despite its not insubstantial two tonne kerb weight, the S8 does better in this regard than something like a Porsche 911 Carrera 4S. Couple that performance to a Tiptronic automatic gearbox, quattro all-wheel drive and some of the most sophisticated traction control electronics yet devised and you have a car that'll be tough to beat in a traffic light grand prix. Add rain to the equation and the Audi's advantage would be even greater.
If you're in any way discouraged by the substitution of the second generation S8 model's Lamborghini-sourced 5.2-litre V10 by this MK3 model's 4.0-litre V8, then don't be. This powerplant can name-drop too - it's essentially the same as that used in Bentley's Continental GT - and with twin turbos, it develops considerably more power than before, the previous 438PS output here boosted to an even meatier 520PS, 100PS more than the same engine will give you in Audi's S6 and S7 models from this era. More importantly, there's even more pulling power than the MK2 S8 offered, with torque up from 540 to 650Nm. That's enough to drag this huge beast to sixty two mph from rest a second quicker - in just 4.2s - with a lovely metallic howl that would continue on to a maximum of nearly 200mph, were it not electronically restricted to 155.
Early first generation S8s were very impressive but driving one often felt like being seated in a very plush cinema. You relaxed in comfort, watching an awe-inspiring display of technical and dynamic fluency but you never really felt very involved in the action. Stung into action by such criticism, Audi's engineers have made more of an effort with more recent versions. The MK2 model got tweaked firmer Sports air suspension and a quattro 4WD system with a more rearward bias. And this MK3 model built on this by going a step further still and including a self-locking differential with a sport differential on the rear axle: thanks to this, during hard driving, the lion's share of the power flows to the outside wheel to literally push this 4WD Brands Hatch boardroom through the corner.
And there's more - much more. There's still lowered sports air suspension, but for this MK3 version it features variable damping which can alter the ride height of the body between three levels for what Audi hopes is a 'multi-faceted driving experience'. It's designed to perfectly complement the standard dynamic steering that adapts both its ratio and boost according to speed and uses slight, nearly imperceptible steering corrections to stabilise handling at the cornering limit.
Drive like this and you'll have selected the most focused of the modes available via the Audi drive select system - 'dynamic'. Or indeed set up your S8 for ultimate performance like a race driver would set up his racecar, via the 'individual' settings. If you're really throwing the thing about, you might want to switch the ESP stability control into its interim 'Sports' setting - which will give you a little more opposite lock leeway before all of the stability and traction controls kick in.
But of course on our traffic-clogged roads, the opportunities for such behavior are few and far between. Usually, you'll want to settle back and switch the system into 'auto' so it can adapt to your driving circumstances as the software thinks fit. Or perhaps you could click back into one of the more easygoing settings: 'comfort' (for a magic carpet air-suspended ride) or 'efficiency' (where all the vehicle's systems become frugally-minded).
It's when you're driving like this that you suddenly start to appreciate something. That this car is almost eerily quiet. And there's a reason for that. The engine deactivates four of its eight cylinders for extra efficiency on part-throttle at low speeds, at which point the car realises that you want greater refinement. In response, an Active Noise Cancellation system cuts in. Four microphones integrated into the headlining record noise in the cabin, which is then analyzed by a computer. If that computer detects intrusive sound elements, it broadcasts an antiphase sound through the stereo system speakers, which combines with the intrusive noise and largely cancels it out.
But of course, there are times when you do want noise - when you're powering through the gears and want to hear exactly what that twin turbo V8 can do. Audi understands that too, so there's a sound actuator in the exhaust system to emphasise the sonorous sound of this thumping 520PS powerplant under hard throttle.
That only leaves the brakes. Some S8s you'll find may feature the expensive option of high performance ceramic discs, offering vastly improved temperature tolerance for the best possible resistance to brake fade and an operating life of up to 186,000 miles in everyday use - four times the lifespan of a steel disc. Just remember to budget for replacements.
How to sum up a MK3 model Audi S8? It's beautifully finished, rides imperiously, isn't falsely modest and is backed up by a sledgehammer punch of acceleration. It's a car that does so much but makes such little fuss about it. Loyal buyers like it that way, valuing capability and discretion. If you want to get somewhere fast and draw no great attention, the S8 is one of the best cars in the business for the task - which is why it's a vehicle so often targeted by those of extremely high net worth.
This third generation version teases out those themes still further. The engine is lower key but harder hitting and the styling will appeal to those who know exactly what those subtle design cues mean. Ultimately, it's a car that credits its owner with a bit of savvy. Someone who demands extreme performance but doesn't want a shouty, showy set of wheels. Sometimes, you see, the car is merely the supporting cast.