Audi S6 vs Infiniti QX30

What's the difference?

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.

Even though it’s almost identical to the Q30, the QX30 manages to feel sufficiently different in suspension tune and cabin ambiance to be considered different.

It’s a disappointing oversight, though, by Infiniti to deny the base GT such basic safety fundamentals as a rear view camera (which Infiniti assures us is being worked on).

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.

The QX30 is one of the first projects to result from a technology partnership formed between the parent company of Mercedes-Benz and the Nissan-Renault Alliance.

In a sign of how worldly the car industry is becoming, the QX30 is built in Nissan’s Sunderland plant in the UK, using the German Mercedes-Benz A-Class platform and powertrains, all under Sino-French ownership via the Nissan-Renault Alliance.

On the outside, the design that first aired on the Q30 is pretty unique. It’s not a subtle car, with deep crease lines along its sides that, according to Infiniti, is an industry first in terms of manufacturing complexity.

When it comes to differences between the two vehicles, it’s minimal at best. There is a 35mm increase in height (30mm from taller springs and 5mm from roof rails), an extra 10mm in width, and extra trims affixed to the front and rear bumpers. Aside from the all-wheel-drive underpinnings, that is pretty much it for the exterior.

The same black plastic overfenders that are fitted to the Q30 are present on the QX30, with 18-inch rims on both the base model GT and the other variant, the Premium.

The dimensions of the QX30 are also an exact match for those on the Mercedes-Benz GLA, with the long front overhang acting as the main visual connection between the two cars.

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 QX30 is obviously very similar to the Q30 in many respects, but the interior is slightly different, with larger, less cosseting seats up front and slightly higher seats in the rear.

The cabin is also lighter in overall appearance, thanks to a paler colour palette.

There are plenty of neat inclusions, including a pair of USB ports, plenty of door storage, a space for six bottles and a sizable glove box.

A pair of cupholders resides up front, along with a pair in the fold-down armrest in the rear.

There is no particularly logical location for the storage of smartphones, though, and the lack of Apple CarPlay or Android Auto is down to Infiniti opting for its own phone connectivity suite.

A decent 430 litres of luggage space behind the rear seats is contrasted by a cramped rear area for all but the smallest of passengers, while sharply shaped rear door apertures making getting in and out a bit of an ask.

There are two ISOFIX baby seat points and a 12-volt socket in the rear, as well.

The QX30 will be offered in two variants; the base model GT at $48,900 plus on-road costs, while the Premium will cost $56,900.

Both come equipped with the same engine; a 2.0-litre four-cylinder turbocharged petrol engine that’s sourced from Mercedes-Benz and also used on the Q30 and Merc GLA.

Eighteen-inch rims are standard on both cars, while an electronic handbrake, 10-speaker Bose audio, 7.0-inch multimedia screen and a full set of LED lamps all round are fitted across both variants as well.

Unfortunately, the QX30 GT misses out on a reversing camera all together, a fate it shares with the Q30 GT. 

Infiniti Cars Australia told us that this was an oversight at the time the cars were being specced for Australia, particularly in light of the other technologies that the car would receive, like automatic emergency braking.

The company says it’s working hard to bring a reversing camera to the GT.

The top-spec Premium gets leather trim, a powered driver’s seat, and additional safety equipment like a 360-degree camera and radar cruise with brake assist.

The only optional extra on each car is metallic paint.

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.

Just the one engine is used across both cars; the 155kW/350Nm single-turbo 2.0-litre four-cylinder petrol engine from the Q30 and A-Class.

It’s backed by a seven-speed transmission and wired into an all-wheel-drive system that is biased towards a front-drive configuration.

Sourced from Mercedes-Benz, up to 50 per cent of drive can be sent to the rear wheels, according to Infiniti.

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.

Infiniti claims a combined fuel economy figure of 8.9L/100km for the 1576kg QX30 across both the variants; this is 0.5L thirstier than the Q30 version.

Our brief test yielded a dash figure of 11.2L/100km over 150km.

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.

Again, it would be easy to think that the QX30 would feel almost identical to its lower-riding sibling – but that would be incorrect. We criticised the Q30 for being a bit too buttoned down and unresponsive, but the QX30 feels more lively and involving, thanks to its unique spring and damper set-up.

Even though it’s 30mm higher than the Q, the QX doesn’t feel it at all, with a benign, pleasant ride with good body roll control and competent steering.

Our front-seat passenger complained of feeling a little ‘hemmed in’, which is a valid point. The sides of the car are very high, and the roofline is quite low, exacerbated by the steeply raked windscreen.

The 2.0-litre four-potter is smooth and punchy, and the gearbox well suited to it, but it’s lacking in aural character. Luckily the QX30 does a terrific job of suppressing noise before it gets into the cabin, then…

The QX30 gets seven airbags, auto emergency braking, forward collision warning and a pop-up bonnet as standard across the line.

The base GT does, however, miss out on a reversing camera.

The Premium model also offers a 360-degree camera, blind spot warning, radar cruise control and brake assist, traffic sign detection, reverse motion detection and lane departure warning.

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.

The Q30 is offered with a four-year, 100,000km warranty, and servicing is suggested every 12 months or 25,000km.

Infiniti offers a fixed three-year service schedule, with the GT and the Premium both costing an average of $541 over the three services provided.