Mercedes-Benz CLA-Class vs Audi S6

What's the difference?

The broadening of the CLA’s scope in this third-gen version puts it a step ahead of key rivals and raises the compact sedan’s prominence in the three-pointed star’s local line-up. Its combination of quality design, performance and efficiency is compelling. And we’ll drive the battery-electric version as soon as it lands.

Note: CarsGuide attended this event as a guest of the manufacturer, with travel, accommodation and meals provided.

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.

In an impressive feat of aero fine-tuning Mercedes-Benz design and engineering teams have managed to make an already slippery car even more efficient with this new CLA dropping the car’s drag-coefficient from 0.23 to an amazing 0.21.

The sloping, coupe-style profile remains as a CLA signature, complete with frameless doors, flush door handles and aero wheels. 

Hybrid variants sport a conventional radiator grille decorated with a Mercedes-Benz star pattern in chrome and illuminated around its perimeter, while the EVs feature a fully illuminated LED grille display.

And in a move perilously close to branding overkill, the three-pointed star motif is carried into the headlights and tail-lights.

For Latin buffs the interior treatment is minimus extremus, the multi-screen ‘MBUX’ array in the CLA220 we drove dominating the front part of the stripped-back cabin.

From an ergonomic point-of-view, there are no physical controls for ventilation and the only non-digital audio control is on the steering wheel.

But aesthetically, the cabin is clean and simple with touches like ‘floating’ door armrests and a gently rounded front centre console adding to an overall relaxed atmosphere.

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.

At just over 4.7 metres long the CLA isn’t a million miles away from full C-Class length and interior space is generous. In fact, there’s an extra 16mm in height and 12mm in width compared to the model this car replaces.

And in terms of storage there are generous bins in the doors with room for bottles and you can place them in one of the two cupholders in the centre console.

There’s the obligatory bin between the seats, a bay here for wireless device charging and a glove box, plus an extra storage bay under the flying buttress-style console.

In the back seat sitting behind the driver’s seat, set for my 183cm position and there’s plenty of footroom as well as acres of legroom and headroom. 

And part of that is the immense panoramic roof which is covered in all kinds of high-tech coatings to make sure all the light comes through but none of the heat.

Then for storage, again you’ve got bins in the doors with room for bottles as well as a pull-down armrest between the seats with three cupholders in it (one espresso-sized) and drive slot in front of them.

There are netted map pockets on the front seatbacks, individual vents which are always welcome and a couple of USB-C charging ports to keep devices charged.

Boot volume is rated at 405 litres (VDA) and the rear seatback folds 40/20/40 to liberate more storage space if required. And there’s a 101L front boot on electric models. 

There’s a hands-free tailgate on the 220 Hybrid. A 1.6- to 1.8-tonne braked trailer towing capacity is handy, but the fact there’s no physical spare tyre isn’t. Your only option in the case of a flat is an inflator and puncture sealant kit. Not good enough.

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.

Hybrid CLAs combine a 1.5-litre, turbo-petrol, four-cylinder internal-combustion engine (ICE) with a 48-volt electric motor integrated into a new eight-speed dual-clutch transmission with drive going to the front wheels in the CLA180 and 200 and all four in the CLA 220 4Matic.

Mercedes-Benz quotes power and torque outputs for the hybrid’s petrol engine and electric motor individually and the powertrain is able to engage both simultaneously so there are overall output figures, as well. 

The pure-electric models are powered by an in-house developed permanently excited synchronous motor driving the rear wheels through a two-speed transmission, with a second 80kW drive unit added to the CLA350’s front axle for extra performance and all-wheel-drive traction. 

Here’s a panel to explain it all.

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.

Hybrid CLAs are fitted with a 48-volt, 1.3kWh lithium-ion battery and at urban speeds where less than 20kW is needed, can drive using electric power alone, depending on conditions at speeds up to 100km/h. 

Official combined cycle fuel consumption is quoted at 5.4L/100km for the CLA180 and 200, which equates to a theoretical range of close to 800km, rising to 5.8L/100km for the 220 4Matic for a potential range of around 740km. 

On the roughly 150km launch drive through Melbourne's suburbs and up the Yarra Valley north-east of the city we saw an average of exactly 5.8L/100km in the CLA220.

Electric CLAs are underpinned by a specific new-gen EV platform boasting an 800-volt electric architecture and housing an 58kWh LFP battery in the 200 electric and an 85kWh NMC pack in the 350.

Maximum charge capacity is 320kW for a claimed 10-80 per cent charge time of 22 minutes. 

Claimed energy use for the CLA200 electric is 14.4kWh/100km with a range of 470km while the AWD 350 4Matic sits at 14.9kWh/100km with a range of 663km.

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.

The CLA220 4Matic was the only option available for the drive program, but for the record, claimed 0-100km/h acceleration times for the hybrid models step down in roughly one second increments - 8.8 seconds for the CLA180, 8.0sec for the 200 and 7.1sec for the 220 4Matic.

Switch to pure-electric power and the CLA200 electric hits the same speed in 7.5 seconds, while the 350 4Matic electric smashes the five second barrier at a properly quick 4.9sec.

Mind you, the 350 4Matic electric weighs about 2.1 tonnes while the hybrids tip the scales at roughly 1.7 tonnes.

There’s plenty of performance in the 220 4Matic but power delivery is not always linear with the powertrain taking half a beat to pick up after you’ve applied some throttle. Which could be the interface between the combustion engine and the electric motor or the turbo on the engine.

The sports steering wheel is grippy and chunky in the hands, and while the steering itself is nice and accurate, road feel is modest. 

There are two settings for steering weight - Comfort and Sport. We tried both, and yes, you can feel where the car’s going but it’s not exactly an intimate connection between your hands and the front tyres on the tarmac.

Speaking of which, standard rubber on the CLA220 is 225/40 Bridgestone Turanza 6 on 19-inch rims and despite those relatively large wheels the car copes well with bumps and thumps and the coarse-chip surface of rural B-roads.  

Suspension consists of a newly-developed strut-based three-link set-up at the front and multi-links at the rear with all of the major components in alloy to minimise unsprung weight.

The car remains composed and balanced through corners and the sports seats in the 220 are grippy, supportive and comfortable. We spent a couple of hours straight behind the wheel without a hint of discomfort.

The CLA’s super-slippery shape manifests itself out on the highway with minimal wind noise at 100km/h and even more. The big tyres are also quiet so the cabin environment remains refined and peaceful.

Brakes on the 220 are vented discs on the front, solid rotors on the rear. And during some pretty challenging downhill twisty sections we leant on them quite heavily. Push hard and they will bite but are not overly aggressive.

The lane-keeping, driver-monitoring and other assistance features are all there, present and accounted for. But more than ticking the box, they work very well.

The media system is driven by a high-capacity unity engine which is often used in gaming and the graphics and animations are super-smooth. And the latest iteration of the Mercedes-Benz media system works nicely across the enormous screens.

All models feature a 360-degree overhead view and a reversing camera and the 11.2-metre turning circle is not small but not vast. The car is easy to manoeuvre and park.

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.

The CLA is covered by Mercedes-Benz Australia’s five-year/unlimited km warranty with roadside assistance included. On top of that, there’s an eight-year/160,000km warranty on the drive battery in electric models.

That general warranty is in line with Audi, BMW and other premium players, but it’s worth noting an increasing number of brands in the mainstream market are stepping up to longer seven, eight and even 10-year cover.

Hybrid and electric variants have the same 12-month, 25,000km recommended service interval with a five-year schedule for the hybrids equating to an average of $1342 per workshop visit over that period. Reduced mechanical complexity in the EV models lowers that number to $859. But neither is especially cheap in the context of class competitors.

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.