Mercedes-AMG A45 S review

We all love a big headline figure, and in a game of Top Trumps the Mercedes-AMG A45 S is the best card to draw out of all the hot hatchbacks.

That’s because its petrol engine develops a whopping power output of 416bhp, which might seem like something you’d find on a performance car, let alone a hatchback. Even more impressive is the AMG A45 S's official 0-62mph time of 3.9 seconds.

There's no big six or eight-cylinder engine to be found under the bonnet of this Mercedes A-Class variant – just a 2.0-litre with four-cylinders (oh, and a turbocharger bigger than your head).

Only one other hot hatch that gets close to the AMG A45 S's manic performance: the Audi RS3. You might also want to consider the less powerful BMW M135 or the Honda Civic Type R. Alternatively, if you don’t mind a coupé roofline, there's the BMW M2.

So is the Mercedes-AMG A45 S actually any good to drive and own, or is it just useful for bragging rights? Read on to find out...

Let’s start with the obvious: the Mercedes-AMG A45 S is indecently fast. Its 2.0-litre four-cylinder turbocharged engine creates 416bhp – more than any other 2.0-litre turbocharged engine in production.

With launch mode engaged (in the dry at least) hardly a single horsepower is wasted as it hunkers down and fires you forwards like few other cars. Even in the rain, we managed a 0-60mph time of four seconds – that’s half a second quicker than a BMW M2 with a manual gearbox managed in the dry.

That’s all well and good, but more important is what happens when you plant your right foot on the A45's accelerator pedal without launch control engaged. With such a big turbo strapped to such a small engine, there must be a long pause before it provides any meaningful punch, right?

Wrong. Pin the accelerator to the firewall and after just the briefest of hesitations the car rockets forward ferociously, firing through its gears swiftly yet smoothly. It delivers the kind of shove that just a few years ago was reserved for supercars with six-figure price tags. 

Another surprise is that this is a turbocharged engine that thrives on revs, with peak power not arriving until a heady 6,750rpm. That's no hardship – you’ll enjoy how the A45's turbo wakes up at around 2,000rpm, and how the power increases in a linear fashion all the way to the redline. It doesn't sound as good as the five-cylinder Audi RS3 but it’s still pretty tuneful for a four-cylinder.

For an even more engaging drive, you can press a button to put the A45's eight-speed DCT automatic gearbox in manual mode and change gears using paddles behind the steering wheel. It's pretty faithful to your requests, and certainly more alert than the RS3's gearbox.

The noise when you fire through the gears is very satisfying, with the exhaust making a crack sound that’s reminiscent of a Le Mans prototype.

Now, if you’re reading this thinking the A45 must be a temperamental beast that behaves like a bear with a sore head in traffic, prepare to be pleasantly surprised. Left in comfort mode, it's as easy to drive as a regular Mercedes A-Class and is happy to trundle along quietly.

The A45's standard adaptive suspension is firmer than on the regular family car but only nasty potholes or manhole covers really cause any discomfort. If you avoid scrappy surfaces, it's actually quite easy to live with by hot hatch standards, although the RS3 fitted with adaptive suspension is more agreeable and doesn’t jostle occupants around in their seat as much. The RS3 also generates less road noise.

So what happens when you turn away from regular roads and on to something more sinewy?

Well, the A45's steering isn't hyper-quick but it does give you a much better sense of connection with the front wheels than you get in the RS3. The Honda Civic Type R has meatier steering that's better still, but (crucially) the A45’s steering always feels natural and precise, making it a cinch to place it exactly where you want it on the road.

Even in Comfort mode, body lean is minimal, and you can easily ramp things up to Sport mode to further reduce it without completely ruining ride comfort. The Sport + and Race suspension settings are a bit too much for all but the smoothest of roads, but you can opt to apply these most extreme modes to the engine and exhaust individually without affecting the ride.

Like the less powerful Mercedes-AMG A35, the A45 has four-wheel drive, but with a much more clever set-up. As well as varying the power split between the front and rear wheels, it can also vary it from side to side at the rear.

The aim? Well, depending on the drive mode you’ve selected, the system can boost traction – and therefore stability – so the rear wheels can receive plenty of power without the nose running wide through corners.

Alternatively, you can use the drift mode, which encourages the car to slide sideways easily when you accelerate hard and steer into a bend. It wrecks tyres and is unsuitable for public roads, but if you like that sort of thing it's a lot of fun.

“I know the Mercedes-AMG A45 S is not quite as civilised as an Audi RS3, but that’s also a big reason for wanting to wake up at the crack of dawn just to go for a blast in it. That’s the best thing you can say about hot hatches that put fun first.” – Lawrence Cheung, New Cars Editor

The Mercedes-AMG A45 S gets plenty of racy touches in its visually striking interior to make sure you know you're not in a standard Mercedes A-Class. They include AMG sports seats in the front and an AMG flat-bottomed steering wheel with dials for changing drive mode settings.

Although it doesn't have adjustable lumbar support, the A45's driving seat has plenty of other electric adjustment as standard (with memory settings). The steering wheel offers a good range of height and reach movement to allow drivers of all sizes to find a comfy posture.

The A45 also adds a bundle of bespoke AMG software to the car’s MBUX infotainment system. It can show engine and gearbox oil temperatures, record lap times and even has a G meter to show handling and acceleration forces.

Indeed, it can log 80 separate feeds of data so you can analyse your on-track performance – although we doubt many buyers will use it more than once or twice. Like having a diving watch that's rated to 200 metres, it’s more about bragging rights than anything else.

You get a 10.3in digital driver's display and an adjoining 10.3in touchscreen. Both have sharp graphics, and the digital instrument panel is highly configurable yet easy to read. In the A45, it also displays AMG-specific graphics, which includes a Supersport mode with a large central rev counter.

Unfortunately, Mercedes has removed the useful physical touchpad that was found on the centre console in the previous-generation A45, so you now have to use the touchscreen or the fiddly touch-sensitive buttons on the steering wheel to control the infotainment system.

We much prefer the physical rotary controller you get in the BMW M135. Other than that, the software is good, with logical menus and quick reactions to all of your inputs.

Arguably, the A45 has nailed it in terms of visual appeal with the interior, thanks to a wide range of materials used coupled with turbine-style air vents that also light up at night and glow like afterburners. That said, the build quality could be better in terms of feeling robust and the Audi RS3 and BMW M135 feel better screwed together.

“I love that you can adjust how the Mercedes-AMG A45 S drives with the controls on the sports steering wheel. Simply turn the right circular dial to select your driving mode then press buttons on the left one to scroll through individual settings. It saves you faffing with the touchscreen.” – Dan Jones, Senior Reviewer

To put it simply, the Mercedes-AMG A45 S is just as practical as any other Mercedes A-Class. That means plenty of space up front for a couple of 6ft-plus adults as well as decent storage.

A couple of tall mates will fit in the back, but can expect to find their knees fairly close to the front seat backs and their heads near the roof. That's also true in the rival Audi RS3, and while the Honda Civic Type R offers significantly more leg room, head room is tighter.

There’s nothing spectacular about the A45's boot space, although it’s quite a bit bigger than the RS3's and capacious enough for a decent load of shopping or luggage for a week away for two. In our tests, we managed to slot six carry-on suitcases below the parcel shelf, compared with only four in the RS3.

The lip at the boot entrance is a bit annoying because its presence means you have to heave heavy items over it rather than simply sliding them in or out. There’s no height-adjustable boot floor on the options list.

“Even though the Mercedes-AMG A45 S has four-wheel drive, the system hasn’t eaten into boot space, so I can still use it as I would a regular A-Class.” – Neil Winn, Deputy Reviews Editor

The Mercedes-AMG A45 S is one of the most expensive hot hatches you can buy, costing significantly more than even the BMW M135. The Audi RS3 costs slightly less than the A45, but both sit at the top of the price point in the hot hatch class.

The A45’s CO2 emissions are high enough to put it in the top 37% tax bracket as a company car but the same can be said for its rivals. If you want a hot hatch with a low BIK tax rate, the closest is the all-electric Hyundai Ioniq 5 N.

Meanwhile, the A45’s official 31mpg fuel economy figure isn’t bad for a car this quick, and in our real-world tests it still averaged a respectable 28.5mpg.

There’s only one trim, but it comes with plenty of standard equipment, including 19in alloy wheels, ambient lighting, a sunroof, climate control, cruise control, a Burmester surround-sound system, heated front seats, adaptive LED headlights, wireless phone-charging, front and rear parking sensors, and a 360-degree view parking camera.

Mercedes came 22nd out of 32 manufacturers in our 2024 What Car? Reliability Survey brands league table. For comparison, Audi finished 24th and BMW was eighth. The A45 comes with a three-year warranty with no mileage limit. You get the same with the BMW M135 but with the Audi RS3 mileage is limited to 60,000 miles.

The five-star Euro NCAP safety rating awarded to the regular Mercedes A-Class doesn't apply to the A45 version, but safety should be strong. Automatic emergency braking (AEB), lane-keeping assistance, blind-spot monitoring and driver attention monitoring are fitted as standard.

“I think it’s a shame the bright yellow paint option is no longer available for the A45, but there are some interesting alternatives around, including the Mountain Grey one with the matt finish.” – Dan Jones, Senior Reviewer

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