Audi S6 review

You might question the decision to offer the Audi S6 and its Avant sibling with a diesel engine. Look beyond the ‘all diesels are bad’ headlines, though, and it’s easier to see why a 3.0-litre V6 was selected for this performance car version of the Audi A6.

Not only are diesels more fuel-efficient than the equivalent petrols, but they also produce more torque – and that’s what you need to make fast progress without really trying.

To assuage any thoughts that it’s a dirty diesel, the S6 has some clever tricks up its sleeve. These are centred around a 48-volt electrical system, which boosts performance and efficiency. For example, it saves fuel while you're cruising by allowing the engine to switch off completely for up to 40 seconds when you lift off the accelerator pedal.

In addition, it recovers energy that would otherwise be lost during braking and stores it as electricity. That's used to drive an electric compressor, which works alongside a regular turbocharger to boost the S6’s low-rev responsiveness.

There’s plenty to get excited about then, but if you’re after something fast yet practical, should you go for the Audi S6 or S6 Avant (estate) over, for example, the 530d M Sport version of the BMW 5 Series? And can it really better a petrol rivals such as the Mercedes E-Class in powerful AMG E53 form? What’s more, does it feel special enough to justify its premium over the luxurious A6 on which it’s based?

In this Audi S6 review, we’ll look at everything from what it's like to drive to how practical it is and how much it will cost you to buy and run. We'll also tell you which trim level we think is the best.

Once you've decided which car to buy, make sure you get it for the lowest price by searching our free What Car? New Car Deals pages. They're a good place to find the best new performance car deals.

If you’re expecting the Audi S6’s engine to be the stereotypical clattery diesel, think again. Thanks to a trick exhaust, it does a passable impression of a big capacity petrol V8.

The S6 doesn’t rev like a petrol, and the Mercedes-AMG E53 gets from 0-62mph faster (4.5sec compared to 5.0sec), but it still makes swift and effortless progress. That's helped by the huge torque that's available between 2000rpm and 4000rpm to push you along.

If you want to stick with a diesel engine, the BMW 5 Series 530d xDrive M Sport is only 0.4sec slower to 62mph and we don’t reckon you’ll feel the difference. That’s surprising when you consider that the S6 has 339bhp and the 530d 282bhp, especially given that both feed their power to all-four wheels for optimal traction. 

Unlike in the standard Audi A6, the S6’s eight-speed automatic gearbox suffers from zero delay when pulling out of a junction or overtaking. That’s largely thanks to its 48-volt electrical system. In fact, the gearbox contributes to the car’s easygoing character, doing a good job of keeping the engine within its ideal operating window. 

When you end up on a twisty road, the S6 never feels particularly sporty and both the 530d and E 53 prove to be more agile and deliver greater steering feedback. Even so, smaller performance cars – including the Alfa Romeo Giulia Quadrifoglio and Mercedes-AMG C63 S Coupe – are what you need if you’re a really keen driver looking for truly effervescent handling. You’ll need deep pockets to buy either of those rivals, though.

The S6 scores better for ride comfort. The optional air suspension (standard on Vorsprung trim) allows you to make the car firmer or softer. In Comfort setting, the car wafts along motorways or back roads with considerable aplomb. Things get a little grislier on really battered sections, especially around town, but it’s still one of the most cosseting cars of its type. A word of warning, though: the optional 21in wheels make the ride a lot more crashy. 

Regardless of which wheels you go for, the main thing you’ll notice while you’re driving along is that there’s a fair amount of road noise – more than you’ll hear in the 530d, for example. Wind noise, on the other hand, is fairly well contained, matching that of its rivals.

Regardless of which trim you go for, the Audi S6 comes with Audi’s Virtual Cockpit, which replaces traditional analogue dials with a 12.3in digital screen. It's an excellent system, being highly configurable and showing a wealth of useful information just below your sightline. In fact, it makes the optional head-up display (standard on Vorsprung trim) an unnecessary luxury.

To the left you’ll find twin touchscreens, the top one measuring 10.1in and covering such things as the radio, navigation and smartphone links (Android Auto and Apple CarPlay are standard). The 8.6in screen just below is dedicated to climate controls and convenience features.

Both screens respond quickly and provide haptic feedback to confirm when you’ve touched an icon. However, you still have to glance away from the road to find the one you want in the first place, and that’s our biggest bugbear. The setup is so much more distracting to use on the move than the rotary controllers in the BMW 5 Series and Mercedes E-Class.

The driving position is much harder to fault. The sports front seats are supportive and come with electric adjustment (including memory recall and lumbar adjustment). Plus, all-round visibility is good in the saloon and class-leading in the Audi A6 Avant estate. You also get parking sensors front and rear, a rear-view camera and bright LED headlights to illuminate the way ahead after dark.

As you’d expect, given how much you’re paying, everything feels beautifully constructed and the materials are plush. Our only complaint is that the interior doesn’t feel significantly more special than those of much cheaper S line models.

Although the Audi A6 – and therefore the S6 – has slightly less front leg room than the BMW 5 Series and Mercedes E-Class, that's a bit like saying the Asian elephant is smaller than the African; the point is that both are big old beasts. What’s more, when it comes to head room, the S6 is unmatched, preventing even six-footers from ruining their hair on the rooflining. 

Thanks to the width of the S6, there’s plenty of space to ensure that driver and front passenger aren’t rubbing shoulders, but it’s slightly annoying that the door armrest is quite short, meaning that people needing to slide the seats a long way back run out of armrest. 

Take a look in the back of the S6 and you’ll find that it beats both its key rivals for head and leg room in the rear seats. Plus, accommodation for three adults sitting side by side is more generous, even though the middle passenger has to straddle a hump in the floor.

Practicality is another area that the S6 impresses. For starters, we managed to fit nine carry-on sized suitcases into the 530 litre boot of the saloon. That matches the amount that we were able to fit in the E 53 saloon’s boot but one more than you’ll fit in the 5 Series. If you need even more space in the S6, the rear seats can be split and folded totally flat in a 40/20/40 configuration. 

Of course, the estate version – the S6 Avant – is even more accommodating, and its tailgate and luggage cover open electrically. However, for the ultimate in load-lugging ability, you’ll need the Mercedes-AMG E 53 Estate.

In terms of purchase price, the Audi S6 will cost you slightly more than the BMW 540d xDrive M Sport but significantly less than the more performance-focused Mercedes-AMG E 53 – in fact, even the top-spec S6 Vorsprung is only slightly more expensive than the entry-level E 53.

On top of that, when it comes to fuel economy, Audi’s decision to go with diesel power gives its car another advantage over the E 53: the S6 promises up to 40mpg if official figures are to be believed, whereas its Mercedes rival returns nearer 30mpg. What’s more, the difference is only likely to grow in the real world when you start putting your foot down.

Compare the S6 to the 540d’s official figures, on the other hand, and it falls slightly short of the up to 50mpg that the BMW promises. What’s more, if you’re open to the world of plug-in hybrids (PHEVS), the BMW 5 Series in 545e form will cost you about the same as the S6 and will give you considerably more miles per gallon and up to 33 miles of pure electric driving.

If you’re a company car driver, you’ll definitely want to take a look at the PHEV 5 Series because its monthly benefit-in-kind tax payments will be far less than the diesel S6's. In fact, if you’re in the lucky position to be considering the S6 as a company car, bear in mind that it attracts a 4% diesel surcharge. 

At least it’s better news when you take a look at the long list of standard equipment that even the standard S6 attracts. Highlights include 20in alloy wheels, privacy glass, keyless start, leather seats (heated in the front), and all the infotainment and visibility aids.

A slightly more expensive Black Edition sits above the standard car in the range, but it only adds styling tweaks, so unless you really love its looks, it's not worth the extra. The top-spec S6 is the Vorsprung, which adds 21in alloys, keyless entry, heated rear seats, a panoramic sunroof, soft-close doors, adaptive cruise control and black ash interior wood trim. It costs a huge price premium, though.

In terms of reliability, the S6 wasn’t included in the 2022 What Car? Reliability Survey but the Audi A6 finished right at the bottom of the luxury car table, losing out to both the 5 Series and E-Class. Audi did manage to beat Mercedes in the manufacturer table, but it still finished below BMW (16th) in a fairly disappointing 21st position out of the 32 brands included.

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