Audi RS4 vs Mercedes-Benz A45

What's the difference?

What a way to send off this generation of Audi RS4 and RS5. The extra focus courtesy of those trick coil overs and drama from the exhaust plus the sharper gear changes deliver the best Audi has done with these RS products. 

There are some compromises, with the suspension favouring outright control over low-speed comfort. It’s also true that the current BMW’s M3 and M4 are more impressive, but when the products are nearly seven years fresher than Audi’s, what do you expect? 

Plus, those looking for a more restrained and polite fast executive sedan (or wagon) will gel with the Audi’s sophistication. There aren’t many of these Competition Plus RS4 and RS5s coming to Australia and they are impressive visually and from behind the wheel. It’s a fitting way to send off the current generations.

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

The Mercedes-AMG A 45 4Matic+ may have grown up a bit in that it’s not as noisy or uncomfortable as the first-generation version which arrived in 2013, But if anything, its more portent than ever. Superb Mercedes-AMG craftmanship, outstanding performance and good value as far as bang for your buck goes.

The RS4 Avant’s 'Progressive Red' metallic helps the black milled 20-inch alloy wheels pop. Its stance is hugely purposeful with wheels tucked right up in the blistered arches courtesy of the lowered ride height — it's how the Avant would have looked in a design sketch.

The visual bulk of the long-roofed RS4 gives it the sort of proportions motoring journalists love to wax lyrical about, even if plenty of buyers still prefer coupes or lifted SUVs. 

The RS5's more flowing, elegant lines match well with the Navarra Blue paint work, silver-accented wheels and conventional leather-appointed seats within. 

Both cars have effectively identical front cabins reflecting Audi’s classy and sleek design language. The integration of technology is pretty good and the RS4’s additional red styling pack really makes it feel sporty within.

When I went to pick up the Mercedes-AMG A 45 S 4Matic+ I walked right past it and then like that lost and confused John Travolta in Pulp Fiction internet memes, wandered around before asking where the car was.

That’s because I was looking for something with a gigantic spoiler on the roof and probably hi-vis green with stripes. But the car assigned to me was the A 45 S in its standard form, and the styling is subtle enough for it disappear into a crowded car park like James Bond into a lavish dinner party.

But like Bond, chances are the A 45 S is the most hardcore person in the room, it just doesn’t walk in announcing it to everybody.

Look closely and you'll see that the A 45 S is not just another small prestige car. There’s the 90mm quad exhaust poking out of the chunky diffuser, the giant 'Panamericana' grille, and the angry looking front apron.

Then, there are the 19-inch matt black alloy wheels wrapped in low-profile Michelin rubber and enormous brake discs with their red calipers, all barely contained by the pumped up front wheel guards which are much bigger than those on a regular A-Class.

The cost option my test car wore was the 'Mountain Grey Metallic' paint, but if anything it made the A 45 look even more covert.

The cabin is small but luxurious and sporty with two-tone leather upholstery (the red and black 'Lugano' leather in my test car is a no-cost option), there’s the microfibre-clad AMG steering wheel, brushed aluminium trim, metal-trimmed pedals and the large display panel (it’s actually two screens joined) is also standard.

The A 45 S is a hatchback measuring 4445mm in length, 1850mm wide and 1412mm tall. Not keen on a hatch but want something with similar dimensions? The CLA 45 S is the A 45 S’s four-door twin-under-the-skin and is just as much of a weapon.

And if you want your A 45 S to look more aggressive, you can option the 'AMG Aero Package' which will see a giant rear wing fitted to the roof.

Or you can buy the Edition 1 version of the A 45 S which includes the big spoiler and shouty design bits to makes sure everybody knows you’re the assassin in the room.

The RS4's cabin is excellent, with a good mix of physical buttons and responsive touchscreens for control. There’s enough storage space for this kind of vehicle, with good door bins and well-sized cupholders in the centre as well as USB-C and -A charge points. 

Audi’s multimedia system is friendly though the large touch targets and dark background aren’t as crisp as those fitted to the latest rivals. The screen isn't as big, either, measuring 10.1 inches for the multimedia item. The RS4 supports wireless Apple CarPlay and Android Auto.

That said, Audi’s 12.3-inch digital driver’s display with bright and poppy mapping software and generous customisation remains right at the head of the pack. 

There is a panel of switches below the touchscreen for climate control, physical selection of the five-or-so drive modes and a collection of helpful buttons on the perfectly-shaped and sized leather-appointed steering wheel.

It lacks F1 or DTM wow-factor compared to the C63 and M3 with their easy-access driver mode buttons and toggles on the steering wheel but the RS4's restrained looks will resonate with those that prefer a bit more elegance inside. 

Neither the RS4 nor RS5's back seats are designed for those over about 175cm. The RS4’s roof is a little higher so it is good enough for most adults but the RS5’s sloping profile compromises things. It has two individual buckets compared to the RS4’s three-wide bench. 

Rear seat passengers get air vents, an individual climate zone, bottle holders in the doors, USB charge points and ISOFIX attachments for the outboard seats, with matching top tethers in the seat backs.

The Audi RS4’s boot is a generous 505L with under floor storage and a netted area on the driver’s side. Folding the 40/20/40 split-fold bench increases space to 1495L. That said, the RS5’s 465L is still very good, though it is not quite as practical in the real world. 

Being fitted with roof rails makes for sleek integration of roof racks for the RS4 to slip roof pods, bike racks or whatever else you might choose to take on a trip away.

Along with good performance and handling, part of the appeal of hot hatches is that they’re practical… to a degree. The A 45 S is a small car, but it has four doors, five seats and a boot.

The cabin is small, no doubt about it, but even at 191cm tall I had plenty of room while driving, the seating position is perfect actually, although sitting behind my driving position saw my knees just touching the seat back.

Headroom is getting limited back there, but I still had space. Could you get away with the A 45 S as a family car? I had my family in it for a while, but there’s just the three of us and my son is pre-school-aged. So, a young, small family, yes… until it starts to grow.

Cabin storage is good with two cupholders in the rear centre fold-down armrest along with small door pockets and seat-back nets. Up front there are another two cupholders, giant door pockets, a big split-opening centre console bin and a tray for the wireless charger big enough to fit an iPhone 11 Pro Max.   

Boot space is good at 370 litres. The big shiny CarsGuide suitcase fitted in easily (see images) and apart from the wide-opening of the boot, another hatch power of practicality is that you can fold the rear seats down to open up more cargo carrying space, and in the A 45 S’s case that’s 1210 litres.

I’ve mentioned the wireless charger but there are also four USB-C ports (two up front and two in the rear), back seat passengers also have directional air vents, which is another bonus, along with dark tinted windows (welcome when my son was sitting back there in his car seat).

The new Mercedes-AMG A 45 S 4Matic+ lists for $93,600. Coming standard are the 19-inch matt black alloy wheels, the quad exhaust and chunky diffuser, Panamericana grille and AMG front apron, the red brake calipers, small roof-top spoiler and privacy rear glass.

Inside, the A45 S comes standard with sport seats and tone-tone leather upholstery – there’s ‘Yellow cut’ leather with contrasting yellow top stitching (or in the case of our car the no-cost option of red and black Lugano leather), and an AMG Performance steering wheel clad in 'Dinamica' microfibre.

Also standard is the large landscape display which is actually two 10.25-inch screens; one for the digital instrument cluster and another for the media system.

There’s also Apple CarPlay and Android Auto, sat nav, a Burmester stereo, 'Mercedes Me' (voice recognition) assistant, digital radio, wireless phone charging, power adjustable and heated front seats, dual-zone climate control, ambient lighting, proximity key, LED headlights and a panoramic sunroof.

The only feature I felt was missing was a head-up display, which needs to be optioned.

In the first year of sale (until the end of 2020) an Edition 1 version of the A 45 S will be sold. Listing for $101,690 the limited edition comes with a tougher look thanks to the addition of the AMG aero package which fits the giant rear wing, along with 19-inch twin-spoke matte black alloy wheels, door decals and AMG performance seats. Oh, and it only comes in 'Sun Yellow.'

Rivals to the Mercedes-AMG A 45 S 4Matic+ come in the form of Audi’s RS3 Avant, the BMW M2 or, and this may seem like an odd suggestion, the Tesla Model 3 hatch. The latter is a pure electric vehicle but has a 0-100km/h time of 3.4 seconds and an output of 335kW… just saying.

Sitting under the A 45 S 4Matic+ in the A-Class range is the A 35 4Matic for a list price of $69,300. The A35 doesn’t come with the big Panamericana grille and the 2.0-litre engine has a lower output but still packs an impressive 225kW/400Nm.

Audi’s 2.9-litre twin-turbo petrol V6 has seen plenty of use across performance products from Audi and Porsche, including the Macan S and Audi S6. 

In the RS4 and RS5 Competition Plus, it develops the same 331kW (at 5700-6700rpm) and 600Nm (at 1900-5000rpm) as the regular car. This makes it an extremely flexible engine that delivers predictable punch anywhere in the power band.

That said, it lacks the explosive character of BMW’s twin-turbo inline six — the figures are only 15kW and 50Nm higher on paper yet the M3’s response is that much more ferocious. 

Audi’s RS division has tried to capture a bit more emotion, retuning the eight-speed torque converter automatic transmission for crisper shifts. This also benefits the RS4’s 0-100km/h sprint time, which falls two tenths to 3.9 seconds in Competition Plus guise. 

The V6 breathes a little easier, too, with a different exhaust. Audi says the extra sound is down to 8.0kg less sound deadening in the car.

There’s more resonance at idle that does feel tiring sitting in traffic idling but the trade-off is a brawny mid-range baritone that develops into a shrill bark approaching the redline.

There may be hot hatches out there which look wilder than the Mercedes-AMG A 45 S 4Matic+ but do they have the most powerful four-cylinder engine ever to go into a mass-produced car? Nope, but the A45 does: it’s a 310kW/500Nm turbo-petrol four.

It doesn’t sound as angry and gravelly as the previous A 45’s engine but it has more grunt (an extra 30kW/25Nm) and is claimed to catapult the hatch from 0-100km/h in 3.9 seconds.

The '4Matic' part of the name indicates the hatch is all-wheel drive and the '+' means it’s a more sophisticated version of the system which allows all of the drive to be sent to one axle, if need be.

What need would that be? The need to drift, of course, which should be up there with other human rights such as clean air, fresh water and free speech.

Yep, the A 45 S comes with 'Drift Mode' (for the racetrack, of course), along with a 'Launch Mode' for perfect-every-time transitions to warp speed.

Changing gears gunslinger-fast is an eight-speed dual-clutch automatic transmission.

The Audi RS4 wagon is rated to use 9.5L/100km in ADR combined cycle (urban/extra-urban) consumption testing while the slipperier RS5 returns 9.4L/100km in the same test. 

We weren’t able to run accurate or particularly relevant fuel figures on the event but the trip computers showed around 12L/100km in both RS4 and RS5. 

While these numbers are high compared to your average passenger car, the Audi is more efficient than BMW's rivals, and gets remarkably close to the hybrid C63 in the real world.

The fuel tank is quite small for this kind of vehicle at 58 litres. That limits the RS4’s theoretical driving range to 611km. 

Unsurprisingly, the Audi RS4 and RS5 require 98 RON premium unleaded petrol. 

Mercedes-AMG says the 2.0-litre, turbo-petrol, four-cylinder in the A 45 S should use 8.9L/100km after a combination of open and urban driving.

My fuel test saw me drive 131km of urban and country roads, plus some motorway sections, and needed 16.9L of premium unleaded petrol to fill the 51-litre tank back to full.

That comes to 12.9L/100km, which is thirsty, but my driving style may have contributed significantly to that high figure.

The time allocated to driving the RS4 Avant Competition Plus was fairly limited and we were sadly unable to sample how the highly adjustable coil over suspension performed where it makes most sense — on the racetrack. 

Still, winding country roads between Sydney and the Southern Highlands served up some challenges, demonstrating how the Competition Plus pack changes the character of the RS4 and RS5. 

The only real negative is comfort, specifically over those horrible plastic speed bumps that litter shopping centre car parks. With adaptive dampers, carmakers can set programs for these kinds of obstacles to soften and stiffen the clever shocks at just the right time. Not so the Competition Plus pack cars, which ride these bumps harshly.

That about does it, though, and everything thing else is a net benefit. The steering system addresses some criticism of the earlier RS4s. Further than a retune, the Competition Plus gets a new rack, that is non-progressive with a fixed ratio of 15:1 (instead of 13.3:1) and 2.4 turns lock-to-lock. The reactions to each input feel a hint more faithful. 

When above 40km/h the coil overs come into their own. Even though the RS4 rides firmly it doesn’t constantly jiggle over small bumps. Over sharp-edged hits, the suspension rounds the hits off so, while you feel them, there’s a sense of control and sophistication. 

Having speed limits to contend with means it is essentially impossible to find the limits of grip of the 275/30R20 Continental SportContact 6 tyres on the road and there isn’t much body roll, either.

The RS4 is still rewarding, though, getting up on its toes just enough through a series of bends to feel engaging. It gives an impression of being quite light and at 1820kg it is now considered featherweight next to rivals.

The RS4's Quattro all-wheel drive system favours the rear wheels when driving normally (60 per cent rear) and can send up to 85 per cent of the drive to the back axle. 

The tweaked electronically-controlled rear limited-slip differential amplifies the throttle steer-ability of the RS4, giving you the confidence to squeeze the gas on exit. 

It helps that the Competition Plus bucket seats are a little thinner and set closer to the floor giving you more feedback. This is the key differentiator between the RS4 and RS5 we drove — the buckets make the car feel alive. 

Strong brakes are made up of 375mm front rotors clamped by six-piston calipers. Optional carbon ceramic brakes with larger 400mm front rotors help save 6.5kg and, if you plan to use the RS4 on track, are a smart buy along with a set of Pirelli P Zero Corsa semi slick tyres ($850). 

Really, though, neither the RS4 nor RS5 are the perfect car for the track. They are plenty capable and fast on the road with just enough fun, reward and character thrown in to keep you coming back for more.

I wasn’t lying in the introduction to this review. The previous A45 was a pretty intense driving experience. The ride felt brutal, the exhaust note screamed and crackled like somebody had set a wheelie bin full of fireworks alight.

And then there was the sweating. I seemed to sweat a lot driving it and there was nothing wrong with the climate control, that just happens to me when I’m under pressure and excited.

So, has the new-generation A 45 S 4Matic+ gone all soft and quiet on us? No, but things have been toned down a tad.

The exhaust note is not as gruff or loud, and even in 'Sport +' and 'Race' mode it’s still quiet enough to pull into a driveway at night without making enemies of your neighbours.

And the ride is also not as harsh, although even in 'Comfort' mode my wife still found it verging on too firm.

The performance and dynamics, however, felt as sharp as ever.

Acceleration is supercar quick at 3.9 seconds. My gawd, you needed a Ferrari F40 to do that in the mid-’80s, and even now the new Mercedes-AMG GT S supercar gets there only a tenth of a second earlier, and it has a twin-turbo V8.

Top speed for the A 45 S is electronically limited to 270km/h. But hot hatches aren’t really about straight-line speed, they’re more about bent-line speed. You know, corners.

So, I took the A 45 S on the twisty roads I take anything that calls itself sporty. The agility of the A 45 S is outstanding thanks to a rigid chassis that handles a change in direction as quickly and easily as you can turn your head.

The brakes bite hard when they have to, and the all-wheel drive hatch scrambles tenaciously out of corners.

A racetrack is really the best place to truly test a serious sports car's limits and our own James Cleary did just that when he drove the A 45 S at its international launch.

As a daily driver, though, for somebody who occasionally likes to get into it on a curvy road the A 45 S is comfortable enough to live with, but hard enough to remain engaging and dynamic when you get the chance to have a squirt.

The Mercedes-AMG A 45 S 4Matic+ received the maximum five-star score when it was tested by ANCAP in 2018.

The safety equipment list is impressive. Along with nine airbags and a 360-degree camera there’s advanced safety tech such as AEB with cross traffic function, blind spot warning, lane keeping assistance, lane change assistance, auto parking and adaptive cruise control.

For child seats there are three top tether points and two ISOFIX mounts across the second row. Small hatches are the easiest cars to put top tether seats in thanks to the good access to the hook point. I fitted my son’s car seat into the back of the A45 S without any problems.

Audi covers the RS4 and RS5 with a five-year/unlimited kilometre warranty which is now the expected norm across the premium part of the market. 

A five-year service plan can be pre-purchased, costing $3630 for both models with maintenance due annually or every 15,000km. 

After the five-year warranty period, owners can choose to extend the service packaging and warranty for two extra years at a cost of $4260. This can be done twice, extending the warranty up to nine years.

The Mercedes-AMG A 45 S 4Matic+ is covered by a five-year/unlimited kilometre warranty.

Servicing is recommended at 12 month/20,000km intervals. Servicing is capped at $850 for the first year’s visit, $1200 for the next and $1600 for the third.