Audi S4 vs Mercedes-Benz CLA45

What's the difference?

The S4 and S5 range continues to represent a great formula for performance you can live with every day. They're arguably the sweetest balance Audi produces, actually. All come fantastically equipped, with cabins that feel truly special, and we’re lucky they can be had in a choice of five bodystyles.  

The new CLA 45 S has knockout performance to match its knockout looks, neither of which are much of a surprise given the ingredients involved.

That said, it is far from perfect, with questions raised over its value and practicality. And for those reasons, we’d be buying the A 45 S hatch instead.

Is the new CLA 45 S worth such a hefty premium over its non-S predecessor? Tell us what you think in the comments below.

The S4 sedan and Avant have scored the bulk of design updates, with all new and recontoured side panels including the sedan’s C-pillar matching what was applied to the A4 earlier this year. 

This is paired with new front and rear facias and lighting for a subtle but extensive rework of the fifth-generation S4’s conservative look. 

The S5 Sportback, Coupe and Cabriolet get S5-specific new lighting and facias, but no sheetmetal changes. As before, the Coupe and Cabriolet ride on a 60mm shorter wheelbase than the Sportback, sedan and Avant.

The S5s also get Matrix LED headlights as standard which do a neat animated sequence when you unlock the car. 

Other visual hallmarks include new S4-specific 19-inch wheels, with S5 stepping up to its own unique 20-inch wheel. The six-piston front brake calipers are appropriately painted red, and there’s S-specific adaptive dampers under there too. All variants aside from the Cabriolet get a lip spoiler on the rear.

On the inside, there’s a new centre console and bigger 10.1-inch multimedia screen, while the Audi Virtual Cockpit driver instrument display now offers a hockey stick-style rev counter in additional to traditional dial layouts.

There’s simply no mistaking the CLA 45 S from its CLA siblings. It’s angry and stylish, at the same time.

Up front, Mercedes-AMG’s signature 'Panamericana' grille insert is large and in charge, flanked by adaptive 'Multibeam' LED headlights that incorporate sinister-looking daytime running lights (DRLs).

The real action, however, is happening below, where the AMG body kit starts to come into frame. It’s delightfully chunky and highlighted by cavernous side air intakes, which hint at the sledgehammer residing beneath a bonnet featuring prominent power domes.

Around the side, the CLA 45 S does its best impersonation of a coupe, with a sloping roof line and a curvaceous glasshouse. It also brings the aggro with a particularly sporty set of 19-inch alloy wheels, which flank pointy side skirts.

At the rear, the CLA 45 S again hints at its performance level, this time with a bootlid lip spoiler, although look past its LED tail-lights and you’ll find the star of the show, a furious diffuser that houses the quad 90mm tailpipes of the AMG sports exhaust system.

Inside, the CLA 45 S is pretty special. While the CLA certainly provides the building blocks, it goes a step further with a number of unique touches.

Your eyes are immediately drawn to the wickedly cool 'Dinamica'-trimmed AMG Performance steering wheel, which not only has paddle-shifters, but also features two ‘display buttons’ that make adjusting vehicle settings on the fly super easy.

Then there are the front sports seats, which are covered in Lugano leather upholstery alongside the armrest door inserts, while artificial cow hide trims the upper dashboard and door shoulders.

Hard plastics? You’ll need to look lower than the soft-touch middle dashboard to find them, as they are primarily confined to the lower sections of the cabin. And yes, some of the switchgear is very cheap for a six-figure performance car.

One personal bugbear, though, is the liberal use of gloss-black trim for the centre stack and console. Not only is it a fingerprint magnet, but it scratches easily, too. The brushed stainless-steel and silver accents elsewhere are nice, though.

While stainless-steel sports pedals also help to make the CLA 45 S stand out from the CLA crowd, it is otherwise a carbon-copy of its siblings, which is no bad thing.

Of course, the headline act is the pair of 10.25-inch displays, with one a touchscreen that is partially concealed by the steering wheel, while the other is a digital instrument cluster.

The former delivers the now-familiar 'MBUX' multimedia system, which is still at the cutting edge when it comes to functionality, especially with its always-on natural voice recognition, which is as good as it gets, albeit not perfect.

There are, of course, more input methods, with two small touchpads located on the steering wheel, while a larger item sits on top of the centre console, supported by a palm rest. There are also shortcut buttons and physical climate controls.

The biggest practicality change among the five S4 and S5 variants is their upgrade to the latest version of Audi’s MMI multimedia system, which steps up to a 10.1-inch touchscreen and drops the scroll wheel from the centre console.

It also boasts ten times the computing power of the version it replaces and uses this and an on-board sim card to access Google Earth maps for navigation and Audi Connect Plus that offers driver information such as fuel prices and parking information as well as point of interest search and weather information, plus the ability to make emergency calls and seek roadside assistance.

There’s also a wireless phone charger, but using Apple CarPlay will still require a cord as per Android Auto.

I only drove the S4 Avant and S5 Sportback at their media launch, which are clearly the most practical of the five, but from our experience with the previous versions, each looks after its occupants well in terms of space and storage. Back seat accommodation is clearly not a priority in the Coupe and Cabriolet, but there’s three other variants if that’s what you’re looking for. 

The Cabriolet can open its automatic folding soft top within 15 seconds, at speeds of up to 50 km/h.

Measuring 4693mm long, 1857mm wide and 1413mm tall, the CLA45 S is actually similar in size to a C-Class but not quite as practical.

Cargo capacity is pretty good, at 460L, but can be increased via the 40/20/40 split-fold three-seat rear bench stowed – an action that can be performed via the boot’s manual release latches, although it doesn’t tumble forward by its lonesome.

Speaking of the boot, four tie-down points are on hand for to help loose loads alongside two side storage nets. Bulkier items will have to contend with a tall load lip. That said, the boot’s aperture is much wider than before, which is good news.

In-cabin storage options are okay, with the glove box decently sized and the map pockets of the net variety, while the central bin is fairly average, although it does house two USB-C ports.

There’s also a standard sunglasses holder and a cubby in front of the centre console’s two cupholders. It isn’t that useful, though, as the wireless smartphone charger takes up most of space alongside a USB-C port and a 12V power outlet.

The front door bins can accommodate two regular bottles each, while their counterparts in the rear take only one apiece. That said, the second row does have a fold-down armrest with another pair of (flimsy) cupholders.

Rear occupants don’t have a whole lot of room to play with, though. Legroom behind my 184cm driving position is pretty decent, at around four centmetres, but headroom is not. In fact, it’s non-existent sitting upright, with the panoramic sunroof not helping matters.

Toe-room is also at a premium alongside precious footwell space, which is reduced by the tall transmission tunnel. As such, the second row is best for up to two adults or three children at a time.

And if there are three occupants abreast, they’ll have to compete for the two USB-C ports, which are located in a fold-out cubby below the central air vents at the rear of the centre console.

For reference, child seats can be fitted in the second row thanks to top-tether and ISOFIX anchorage points, although both are only available for the outboard seats.

Priced from $111,200 plus on-road costs, the CLA 45 S is a staggering $20,530 dearer than its non-S predecessor. Yep, it’s a hard number to digest at first, but Mercedes-AMG says the premium is justified due to a significant step-up in specification.

Standard equipment not already mentioned includes dusk-sensing lights, rain-sensing wipers, a tyre repair kit, power-folding side mirrors with heating, rear privacy glass, satellite navigation, Apple CarPlay and Android Auto support, digital radio, a 590W Burmester sound system with 12 speakers, keyless entry and start, dual-zone climate control, power-adjustable front seats with heating, an auto-dimming rearview mirror and LED ambient lighting.

Key options include the $2490 'AMG Aerodynamics Package' (high-gloss black front splitter, aero flics and larger bootlid lip spoiler), $3290 'AMG High Performance Seat Package', $790 cooled front seats and $790 'Communications Package' (windshield-projected head-up display). Only the latter was fitted to our test vehicle alongside no-cost 'Polar White' paint.

The CLA 45 S only has one direct rival, the $86,500 Audi RS3 sedan, although the $106,900 BMW M2 Competition coupe is more or less in the same league. Either way, the CLA 45 S is in another league when it comes to price and performance.

But you could also opt for its A 45 S hatch sibling for ‘just’ $93,600…

Audi has taken an ‘if it ain’t broke’ approach with the mechanicals, with all S4 and S5 models unchanged with this update. So the centrepiece continues to be the single-turbocharged 3.0-litre V6 that produces 260kW and 500Nm, with the latter available from a broad 1370-4500rpm.

The rest of the drivetrain is also unchanged, with the venerable but excellent ZF eight-speed torque converter auto paired with the Quattro all-wheel drive system that can send up to 85 per cent of drive to the rear wheels. 

The CLA45 S is motivated by the most potent series-production four-cylinder engine yet.

The 2.0-litre turbo-petrol unit punches out an astounding 310kW of power at 6750rpm and a significant 500Nm of torque from 5000-5250rpm – a marked 30kW/25Nm improvement over its non-S predecessor.

It’s also worth noting Mercedes-AMG performed “torque shaping” to make the new engine’s output delivery (or curve) akin to that of a naturally aspirated unit. This attitude also led to a screaming redline of 7200rpm.

An eight-speed dual-clutch automatic transmission is responsible for swapping gears, while Mercedes-AMG’s fully variable '4Matic+' system sends drive to all four wheels, although it does have a 'Drift Mode' that effectively disengages the front axle.

With the help of standard launch control the CLA 45 S sprints from a standstill to 100km/h in four seconds flat, while its top speed is electronically limited to 270km/h.

Official combined fuel figures range from 8.6L1/00km for the S4 sedan to 8.8L/100km for the Avant, Coupe and Sportback, while the heavier Cabriolet steps up to 9.1L/100km. 

All are pretty good considering their performance potential and the size of these cars, plus the fact that they only require 95 RON Premium Unleaded fuel.

All have a 58-litre fuel tank, which should enable a range of at least 637km between fills based on the Cabriolet’s figure.

Fuel consumption on the combined-cycle test (ADR 81/02) is 8.9 litres per 100 kilometres for the CLA 45 S, while its claimed carbon dioxide emissions are 202 grams per kilometre. Both are pretty keen given the level of performance on offer.

In our real-world testing, we averaged 12.0L/100km over 270km of driving evenly split between city traffic and highways. This result was somewhat inflated by some ‘spirited’ driving but is certainly something we can learn to accept.

For reference, the 51L fuel tank in the CLA 45 S takes 98 RON premium unleaded petrol at minimum.

The S4 and S5 range were already an excellent balance between everyday comfort and a genuine sporting edge, and nothing has changed with this update.

I spent time behind the wheel of the S4 Avant and S5 Sportback at their media launch, and both managed to deliver the proper Audi luxury experience over some pretty rough rural roads, while always feeling a bit more sporting than a regular A4 or A5. That’s with the Drive Select left in the default mode, but you can shift that sporting personality up a few notches (while scaling back the comfort), by selecting Dynamic mode. 

My preferred means of adjusting their personality is by simply tugging the transmission selector back to activate S mode, which livens up the engine and transmission without stiffening up the suspension. 

Across the five S4 and S5 bodystyles, there is some variance in performance potential, with the S4 sedan and S5 Coupe topping the performance chart with 0-100km/h boasts of 4.7s, with the S5 Sportback trailing them by 0.1s, the S4 Avant by a further 0.1s and the Cabriolet managing a still-fast 5.1s claim.

Another area I consider the S4 and S5s to get just right is their exhaust note. It is adaptive, but there’s nothing synthetic about it, and the generally muted and distinctly V6 burble is always there to remind you that you’re aboard a proper performance model, but not in such a way that it will annoy you, or your neighbours. Polite performance, if you will.

When it comes to sheer driving pleasure, the CLA 45 S is a huge step-up over its non-S predecessor.

Of course, the 2.0-litre turbo-petrol four-cylinder engine will steal all the headlines, and rightfully so; it’s the most potent unit in its class by some margin.

In reality, it absolutely slaps. Simply put, acceleration is addictive, and not just because of the outputs, but also the way in which they’re delivered.

The CLA 45 S does its best impression of natural aspiration, and I can’t help but award it an automotive Oscar.

Don’t get me wrong, performance is still strong down low (despite a hint of turbo lag), with it progressively building into, and through, a hard-hitting mid-range before reaching a knockout top end that you’ll want to revisit time and time again.

That said, it does take two to tango, and what a dancing partner the eight-speed dual-clutch automatic transmission is.

It’s almost flawless, with its gear changes stereotypically super quick but uncharacteristically buttery smooth at the same time.

Responsiveness is another strong point, although it does sometimes have difficulty recognising when the fun is over, as it can hold onto the short lower gears for a little longer than necessary.

And despite our initial fears, the CLA 45 S is still very, very vocal, with its sports exhaust system serving up plenty of aural pleasure, albeit not quite as much as the original CLA 45.

The soundtrack is booming and is complemented by plenty of pops on downshifts and the overrun as well as frightening crackles when aggressively up-shifting . But these theatrics require the Sport Plus drive mode to be engaged, which opens up an all-important exhaust valve.

Given the level of performance on offer, you’d be right to assume the CLA 45 S has a firm ride, but it’s actually better balanced than most.

The 'AMG Ride Control' sports suspension on hand consists of MacPherson-strut front and multi-link rear axles with three-stage adaptive dampers, which progressively stiffen things up.

However, all is relatively comfortable, even in the stiffest setting. In fact, only sharper edges are felt. It’s more than liveable, especially considering the benefits of the trade-off.

Speaking of which, the CLA 45 S loves to eat up corners. Handling is more or less neutral when pushing hard, at which point its 1687kg kerb weight starts to be felt.

Nonetheless, body control is very strong, partially thanks to the reinforced chassis, with only a hint of roll encountered when cornering with intent.

A lot of the credit has to go the fully variable 4Matic+ all-wheel drive system with rear torque vectoring, which provides outstanding grip, even in the poorest of conditions.

In fact, it bestows such confidence you'll want to push harder to try and find the limits of adhesion. A staggering effort.

The CLA 45 S isn’t without its flaws, though, with the electric power steering on tap good but not great.

It’s speed-sensitive and has a variable ratio, which mean it’s pleasingly light in hand at low speed and noticeably heavier at high velocity, with the latter exacerbated when playing with the available drive modes.

Either way, it’s nice and direct and provides a good amount of feedback through the wheel, but we feel Mercedes-AMG could’ve taken it even further in these two departments to really mix it up with genuine sports cars.

What isn’t half-baked, though, is the 'AMG High Performance braking system', which consists of 360 x 36mm front and 330 x 22mm ventilated discs with six-piston fixed and single-piston floating red callipers respectively.

This set-up washes away speed with ease, instilling the driver with even more confidence when tackling a winding road, while pedal feel is good. Yep, the CLA 45 S decelerates nearly as well as it accelerates.

ANCAP awarded the CLA range (excluding CLA35 and CLA45 S) a maximum five-star rating in 2019.

Advanced driver-assist systems (impressively) extend to autonomous emergency braking, lane-keep assist, active blind-spot monitoring, cross-traffic alert, adaptive cruise control, traffic sign recognition, high-beam assist, driver-attention alert, hill-start assist, tyre pressure monitoring, park assist, surround-view cameras and front and rear parking sensors. Yep, you’re not left wanting here.

Other standard safety equipment includes nine airbags (dual front, front and rear side, and curtain plus driver’s knee), the usual electronic traction and stability control systems, anti-skid brakes (ABS) and brake assist (BA), among others.

Audi continues to offer a three year, unlimited kilometre warranty, which is in line with BMW but lags behind the five years offered by Mercedes-Benz these days. This also contrasts with the five year norm among mainstream brands, which is punctuated by the seven year warranties of Kia and SsangYong.  

Service intervals are a convenient 12 months/15,000km though, and the same five year ‘Audi Genuine Care Service Plan’ offers capped price servicing for the same $2950 total over five years applies to all S4 and S5 variants. This is only marginally more than the plans offered for regular petrol A4 and A5 variants, so you’re not being stung for the thoroughbred versions.

Like all Mercedes models, the CLA 45 S comes with a five-year/unlimited-kilometre warranty, which sets the standard in the premium market. Better yet, five years of roadside assistance is also bundled in.

CLA 45 S service intervals are every 12 months or 20,000km, whichever comes first. A three-year/60,000km capped-price servicing plan is available for $3750, which is not cheap. That said, its pricing can be reduced by $750 if paid upfront alongside the vehicle.