BMW 540i vs Audi S6

What's the difference?

Not all superheroes wear capes, and we're proud to report the 530e does its bit for green motoring without feeling the need to shout about it. And with no price or specification penalty, it's easier being green than ever before, and the pricing of this BMW really puts the cat amongst the canaries.

We adore the new S6 sedan. It looks great, feels comfortable and goes like stink all at the same time. What’s not to like?

It also helps that it is relatively good value, safe and practical by large-sedan standards, so it’s a bit of a no-brainer.

But will buyers be quick to dismiss the new S6 sedan because it’s not a more practical SUV? Time will tell, but we hope not.

Does the new Audi S6 sedan represent the best mix of executive style and boy-racer performance? Tell us what you think in the comments below.

Crucially, there's nothing weird about the way the 530e looks. While some green cars look like they've been designed by one of the kids from 3rd Rock from the Sun, the 530e looks much the same as the rest of the range, save a few tiny but telltale giveaways - like the e-drive badging outside, and what looks like a bonus fuel flap tucked in behind a front wheel that houses the whole plug-in bit.

And we really, really like it. It's elegant and statesman-like from every angle, and looked especially important in the deep-blue colour of our test vehicle. It's not over-designed, with body creases used sparingly, and the occasional glint of polished silver that rings the windows and the grille adds a final sense of shininess to an understated design. 

Inside, there's more going on than you might normally find in a BMW. The hugely complicated digital display screen now includes everything from battery charge, power usage to the usual assortment of speedometers and petrol readouts. 

It doesn't feel overdone or crazily festooned, but there's more at play here than in your usual BMW.

The dash is busy, too, with a wide screen emerging from a centre stack that also houses a CD player and a digital aircon setup, which in turn sits above a complex centre console from which you can alter driving settings, control the multimedia or cycle through electric modes. It doesn't feel overdone or crazily festooned, but there's more at play here than in your usual BMW.

Elsewhere inside, the seats are beautifully designed, with a quilted leather highlight through the middle, while the gloss-black strip that lines the dash hides a dual strip of ambient interior lights that also runs across all four doors.

To these eyes, the new S6 sedan is very attractive, albeit not outlandish, in keeping with its executive focus.

Up front, the subtly aggressive S body kit immediately comes into frame, with the bumper sporting sinister-looking side air intakes.

And, of course, there’s Audi’s signature Singleframe, which is not only large and in charge, but also finished in gloss-black, like many of the S6 sedan’s exterior design elements.

Below the heavily creased bonnet, the HD Matrix LED headlights look both angry and sophisticated, with their integrated LED daytime running lights (DRLs) providing a crisp signature.

Around the side, the S6 sedan goes about its business quietly, but its blistered wheelarches do add some bulk and help to accentuate its strong shoulder line.

And then there are the thick skirts and 21-inch alloy wheels (with a space-saver spare), which have a sporty twin five-spoke design. It’s all very classy.

Speaking of which, the rear end is arguably the S6 sedan’s best angle thanks to its wicked LED tail-lights, which have a segmented signature.

The chunky bumper below incorporates a diffuser element that houses the quad exhaust tailpipes, while a blink-and-you’ll-miss-it bootlid spoiler rounds out the look.

Inside, the S6 sedan is a technological tour de force, with 10.1- and 8.6-inch touchscreens dominating its centre stack. The former is responsible for most of Audi’s latest multimedia system’s functions, while the latter takes care of the climate controls.

This set-up works pretty well, although a few too many taps are required for certain functions, and then there’s the issue of the glass display coverings, which are absolute fingerprint magnets alongside the gloss-black accents used throughout.

That said, the 12.3-inch digital instrument cluster and windshield-projected head-up display on hand are brilliant. In fact, they set the standard for the entire industry thanks to their design and breadth of functionality.

The S6 sedan does, of course, feel a little bit more special than the regular A6 inside, with the obvious additions being the front sports seats, which are covered in supple Valcona leather alongside the armrests. They even have diamond-stitched inserts.

Then there’s the obligatory flat-bottom steering wheel (with paddle-shifters), which is trimmed in Nappa leather alongside the gear selector, upper dashboard, door shoulders and knee rests. Indeed, hard plastics are hard to find here.

Meanwhile, a black headliner adds to the sportiness alongside the black Alcantara door inserts, but the cabin is otherwise a familiar (read: classy) affair.

As the world's motoring tastes shrink faster than a lap-banded Clive Palmer, it's easy to forget the joys of the full-size sedan, but the space for passengers and luggage in the 5 Series will have you questioning your downsizing ways.

Upfront, there's plenty of room between front-seat riders, who will also share two smallish cup holders, along with room in each front door for bottles. There's also a dedicated wireless charge pad (which, because of its tight design, is crazy difficult to actually remove your phone from), but you'll also get two USB points and a power outlet that's hidden in the sizeable centre storage bin as standard fit.

Backseat riders get heaps of space, both in width and in leg room behind the front seats. And there's twin air-con temp controls and twin power outlets, too. But middle-seat passengers will be forced to sit with their legs on either side of the raised tunnel, which will definitely impact on comfort.

The boot's still sizeable, despite shrinking slightly to house the battery/fuel tank setup

Best to ditch the fifth passenger, then, and deploy the pull-down seat divider, which also houses two cup holders. Finally, there are three ISOFIX attachment points, one for each seat in the back.

The boot's still sizeable, despite shrinking slightly to house the battery/fuel tank setup (the tank has been moved further back to accomodate the batteries), and can be adjusted to be a flat load area if you'd like, offering up to 410 litres with the rear seats in place.

Measuring 4954mm long, 1886mm wide and 1446mm tall, the new S6 sedan is a large sedan in every sense of the term, which is mostly good news when it comes to practicality.

Cargo capacity is decent, at 520L, but can be increased to an undisclosed amount with the 40/20/40 split-fold rear bench stowed.

Speaking of the boot, there are four tie-down points and a cargo net to help secure loose loads, while a bag hook and a side storage net are also on hand, alongside a 12V power outlet. Bulkier items will, however, be confronted by a decent load lip.

In-cabin storage options are numerous, but not all are effective. The glovebox is well-sized, while the driver-side cubby is surprisingly large, but the central bin is shallow, mostly taken up by the wireless smartphone charger, two USB-A ports and the SD and SIM card readers.

A pair of cupholders is located in the centre console, with a 12V power outlet found in between, while the front door bins can accommodate one regular bottle each, just like their rear counterparts.

In the second row, there’s a fold-down armrest with two more cupholders as well as a shallow storage tray, while cargo nets are affixed to the front seat backrests.

The rear bench is pretty comfortable, with four inches of legroom available behind my 184cm driving position alongside decent toe-room. Headroom is also good, with about two inches on offer.

That said, three adults sitting abreast won’t enjoy the experience, due to the large transmission tunnel, which makes for limited footwell space. At least they’ll have access to a couple of USB-A ports and a 12V power outlet, below the central air vents.

For reference, child seats can be fitted to the outboard seats via top-tether and ISOFIX anchorage points.

The new S6 large sedan is priced from $149,900 plus on-road costs and is far better value than before, even if it does command a $33,900 premium over the regular A6's flagship variant.

Compared to its predecessor, the new S6 sedan is $21,480 cheaper, while Audi Australia claims it has also added $20,000 worth of kit.

Standard equipment not already mentioned includes metallic paintwork (our test vehicle was finished in Tango Red), dusk-sensing lights, rain-sensing windshield wipers, soft-close doors, auto-folding side mirrors with heating, rear privacy glass and a hands-free power-operated bootlid.

Inside, satellite navigation with live traffic, Android Auto and wireless Apple CarPlay support, digital radio, a 705W Bang & Olufsen 3D sound system with 16 speakers, a panoramic sunroof, keyless entry and start, power-adjustable front seats with heating, a power-adjustable steering column, four-zone climate control, an auto-dimming rearview mirror and LED ambient lighting feature.

Of note, buyers can opt for the $7700 Dynamic Package that bundles in speed-sensitive electric power steering, a rear limited-slip differential and all-wheel steering. It was not fitted to our test vehicle.

In terms of rivals, the BMW M550i sedan is identically priced, while the Mercedes-AMG E53 sedan is much more expensive, at $173,800. The S6 sedan arguably has the former beat on value but loses the performance battle due to its 390kW/750Nm 4.4-litre twin-turbo V8.

Drift around in pure EV mode and you'll be relying on the 530e's 83kW and 250Nm electric motor, which will provide what BMW refers to as "between 28 and 32 real-world kilometres".

Run out of range, or simply use too much throttle, and the 2.0-litre petrol engine comes into play, adding 135kW and 320Nm to the mix. All up, that's 185kW and 420Nm - respectable numbers by any measure, and enough to match the petrol-powered 530i's zero to 100km/h sprint of 6.2 seconds.

That power is fed through an eight-speed automatic transmission before being sent exclusively to the rear wheels, where it belongs.

The new S6 sedan is powered by a hard-hitting 2.9-litre twin-turbo V6 petrol engine that produces a strong 331kW of power from 5700-6700rpm and a punchy 600Nm of torque from 1900-5000rpm.

Compared to its aforementioned predecessor, power is unchanged, while torque has increased by 50Nm.

This unit is mated to a 48V mild-hybrid system that includes a trick Electric-Powered Compressor (EPC), which helps to reduce its turbo lag.

A reliable eight-speed torque-converter automatic transmission is responsible for swapping gears, while drive is sent to all four wheels via Audi’s rear-biased quattro system.

This combination helps it sprint from a standstill to 100km/h in an impressive 4.5 seconds, while its top speed is electronically limited to 250km/h.

Like a Facebook relationship status, it's complicated. The 530e will sip a claimed combined 2.3 litres per hundred kilometres on the claimed/combined cycle, which is amazing for a car this size. Better still, it seems genuinely achievable - at the vehicle's launch, our own Richard Berry recorded a stunning 2.0 litres per hundred kilometres on a short test route.

But that's with a full load of battery charge on board. For our week with the 530e we were unable to actually plug it in (living in Sydney, I can't afford a garage), so once the initial battery charge had been used we were back to mostly petrol power. Unlike some other plug-in hybrids we've driven, we found it very difficult to recharge the battery to any meaningful level using regenerative braking, so once we were flat we stayed flat. If we had plugged it in, it would have been a two-hour recharge using a specialised wall unit, or about four hours using a normal plug.

As a result, though, our fuel use was closer to 7.0 litres per hundred kilometres after some considerable real-world testing.

The new S6 sedan’s fuel consumption on the combined-cycle test (ADR 81/02) is 8.4 litres per 100 kilometres, while claimed carbon dioxide emissions are 197 grams per kilometre. Both figures are pretty keen given the level of performance on offer.

Audi says the aforementioned 48V mild-hybrid system reduces fuel consumption by 0.4L/100km thanks to its coasting ability, which sees the engine turn off for up to 40 seconds between 55km/h and 160km/h. It also engages idle-stop from 22km/h.

In our real-world testing, we averaged 14.4L/100km over 100km of driving skewed towards country roads over city traffic, with limited highway time. It’s worth noting that my spirited driving inflated this result. That said, while its fuel consumption is not as bad as it appears, this is still a thirsty sedan.

For reference, the S6 sedan’s 73L fuel tank takes 98RON petrol at minimum.

There's so much to like about the way the 530e sets about saving the world, and that's mostly because it doesn't shout about it, either to the driver or the outside world.

It's very much an underpants inside its pants superhero, which makes us like it even more. Set off in EV mode, and the 530e will drift silently away from the curb, burning battery power over fuel for as many as 30(ish) kilometres. But equally important, the shift from green to gas is largely imperceptible, with the petrol engine joining in willingly when you ask it to - usual via a prod of your right foot.

It is so effortlessly smooth that you need to really pay attention to notice the eight-speed 'box changing gears at city speeds, and it's commendably quiet, whichever drive mode you're in.

Downsides? Well, it doesn't feel quite as sharp as it's conventional-engined siblings. The batteries add around 230kg in weight, which never helps, and it all feels a little softer and a little less dynamic, even with Sport mode engaged. BMW assures us the adaptive suspension setup and tune is identical, but the 530e feels noticeably softer when you tackle a twisting back road. And that encourages you to use your right foot a little more, which in turn negates the whole electric thing in the first place.

One of the great joys of BMWs has always been their ability to transform from cosseting comfort to rear-drive rocket when you want them to, and you can't help but notice the 530e isn't quite up to that challenge. But if your intentions are mostly city- and freeway-based, then this plug-in BMW is almost indiscernible from its petrol-powered sibling.

The S6 sedan has no right being this good in a straight line and around corners…

Much of its success is owed to the 2.9-litre twin-turbo V6, which is now one of my favourite engines being built today. Simply put, it absolutely hammers.

Punch the accelerator from a standing start and it doesn’t take long for 600Nm to be on tap all the way through, and just a little bit beyond, the mid-range.

Occupants are firmly pressed into their seats as the S6 sedan sprints towards the horizon with vigour. Soon enough, 331kW arrives and hangs around until just prior to the redline.

Needless to say, this acceleration is addictive, and the EPC deserves some of the credit, as it effectively mitigates any dreaded turbo lag and ensures the engine is always seemingly on boost.

But we also need to acknowledge the eight-speed torque-converter automatic, which is a real beauty. Gear changes are nice and smooth, which is great, but what’s even better is their relative quickness – dual-clutch transmissions be damned!

Of course, extra performance can be extracted by switching between the engine and transmissions’ settings but, rest assured, they both stand up, no matter what.

However, we’d suggest spending time in the former’s most aggressive setting, as it unleashes the sports exhaust system, which sounds unreal.

Upshift with intent and you’re met with a booming ‘brap’. Downshifts and the overrun will even gift you a series of pops. In fact, the S6 sedan soundtrack sounds strangely similar to that of the five-cylinder RS3, and we have absolutely no problem with that.

Better yet, the S6 sedan has an appetite for corners, with its neutral handling a standout, partly thanks to its hard-working rear-biased quattro all-wheel-drive system, which works in tandem with all the other electronics to ensure there is plenty of grip at any given time.

This controlled driving pleasure is enhanced by the electric power steering on hand, which has a variable ratio. At low speed, it’s nice and light, but those after more heft can always switch to another one of its settings, which become progressively heavier… arguably too heavy.

Feedback through the wheel is also good, while the steering itself is pretty direct, lending itself to sporty driving, which, of course, is half of the S6 sedan’s mantra.

Coming into corners, braking performance is solid, thanks to the massive 400mm front and 350mm rear discs with red callipers, so the driver is brimming with confidence at every turn, even though there’s an unladen weight (with 75kg driver and luggage) of 1985kg to manage.

But let’s not forget the S6 is an executive sedan, so it has to ride like one. Thankfully, it does. The independent five-link suspension has air springs and adaptive dampers, which serve up comfort in spades, especially at high speed.

Its firm tune does come into frame when travelling on unsealed or uneven roads, with this exacerbated by the large 21-inch alloy wheels, which have a penchant for catching sharp edges.

ANCAP awarded the A6 range (including S6) a maximum five-star safety rating in 2018.

Advanced driver-assist systems extend to autonomous emergency braking with pedestrian detection, lane-keep and steering assist, blind-spot monitoring, rear cross-traffic alert, adaptive cruise control with stop-and-go functionality, high-beam assist, driver attention alert, hill-start assist, tyre pressure monitoring, surround-view cameras and front and rear parking sensors. Yep, buyers aren’t left wanting here.

Other standard safety equipment includes six airbags (dual front, side and curtain), electronic stability and traction control systems, anti-skid brakes (ABS), brake assist and electronic brake-force distribution, among others.

Like the rest of the 5 Series range, the 530e falls under BMW's three-year, unlimited-kilometre warranty. There are no set service intervals, either, with BMW using what it calls 'condition-based' servicing. In other words, the car will tell you when it requires a trip to the service centre.

The batteries are covered by a separate warranty covering six years or 100,000km.

The S6 sedan comes with Audi Australia’s three-year/unlimited-kilometre warranty, which falls short of the premium market’s relatively new five-year standard that was set by Genesis and followed by Mercedes-Benz.

Three years of roadside assistance is also bundled in, although this term can be extended up to nine years if the vehicle is serviced at an authorised dealership, which is great.

Speaking of which, service intervals are every 12 months or 15,000km, whichever comes first. Capped-price servicing plans are available, costing $2350 for three years/45,000km or $4110 for five years/75,000km. They’re pricey, but you weren’t expecting the opposite.