Mercedes AMG A45 review

Four hundred and sixteen brake horsepower. That might seem like the power figure for a performance car, but it’s actually how much grunt the Mercedes-AMG A45 S packs under its hot hatchback exterior.

Even more impressive than the AMG A45's headline power figure and its official 0-62mph time of 3.9 seconds is how it achieves them. You see, 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 four-cylinder (oh, and a turbocharger bigger than your head).

There’s really only one other hot hatch that gets close to its manic performance: the Audi RS3. You might also want to consider the less powerful BMW M135i 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 accelerator pedal without launch control engaged. With such a big turbo strapped to such a small engine, there must be loads of lag, right?

Wrong. Slam 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's a wonderfully addictive experience and delivers the kind of shove that just a few years ago was reserved for six-figure supercars. 

Another surprise is that this is a turbocharged engine that thrives on revs, with peak power not arriving until a heady 6,750rpm. Not that this is a hardship – you’ll enjoy how the 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 ‘mere’ four-cylinder.

For an even more engaging drive, you can press a button to put the car's eight-speed DCT automatic gearbox into manual mode and change gears by pulling 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, 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 the regular Mercedes A-Class and is happy to trundle along quietly.

Its 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, proving far softer than the sometimes jarring Honda Civic Type R. The RS3 fitted with adaptive suspension is even more agreeable, though.

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

Well, the 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 Civic Type R’s steering is 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 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 either boost traction and therefore stability, or if you've decided to take your A45 on to a racetrack, can encourage it to drift sideways creating lots of smoke.

On the road, the rear wheels always seem happy to receive plenty of power to prevent the nose running wide through corners – but then there's Drift mode...

It doesn’t make the car fully rear-wheel drive – which the equivalent setting in the larger Mercedes-AMG E63 does – but it does help the car to slide sideways easily when you accelerate hard and steer into a bend. It wrecks tyres and is unsuitable for public roads, so it's a bit of a gimmick really.

Performance overview

Strengths Amazing straight-line performance; sharper handling than an Audi RS3; great engine sound

Weaknesses Ride is firm but acceptable for a hot hatch; drift mode is a bit of a gimmick 

On top of the visually striking interior of the standard A-Class the Mercedes-AMG A45 S gets plenty of racy touches.

They include AMG sports seats in the front, an AMG flat-bottomed steering wheel with touchpad controls, and AMG-specific graphics for the digital instruments, which include a Supersport mode with a large central rev counter.

Although it doesn't have lumbar adjustment, the driver’s seat has plenty of other adjustments, and in combination with a steering wheel that offers decent amounts of reach and rake adjustment, allows drivers of all sizes to find a comfy posture. Electric seat adjustment comes as standard.

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 a G meter to show handling and acceleration forces.

It can log 80 separate feeds of data so you can analyse your on-track performance. It’s something we doubt many buyers will use 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 display and an adjoining 10.3in infotainment touchscreen. Both have sharp graphics and the ‘virtual’ instruments are highly configurable yet easy to read.

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

We much prefer the physical rotary controller you get in the BMW M135i. Other than that, the software is good, with logical menus and quick reactions to all of your inputs.

Interior overview

Strengths Figure hugging seats; racy touches make it feel special; impressive AMG infotainment software; great driving position

Weaknesses Seats don’t get adjustable lumbar support

To put it simply, the Mercedes-AMG A45 S is just as practical as any other A-Class. That means plenty of space up front for a couple of 6ft-plus adults as well as decent oddment 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 boot, although it’s quite a bit bigger than the RS3's and capacious enough for a big weekly shop or 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.

Practicality overview

Strengths Just as practical as a regular A-Class; plenty of space for taller drivers; enough head and leg room for six-footers in the back

Weaknesses Annoying boot lip; no height-adjustable boot floor

The Mercedes-AMG A45 S is one of the most expensive hot hatches you can buy, costing thousands more than even the BMW M135i. The Audi RS3 costs a similar amount to the A45.

The model's CO2 emissions put it in the top 37% company car tax bracket. However, its 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, a Burmester surround-sound system, heated front seats, adaptive LED headlights, wireless phone-charging, front and rear parking sensors, a 360-degree parking camera, blind-spot assist and lane-keeping assist.

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

Mercedes came 24th out of 32 manufacturers in our 2023 What Car? Reliability Survey brands league table. For comparison, Audi came 26th and BMW was 12th. The A45 comes with a three-year warranty with no mileage limit. You get the same with the M135i, but with the RS3, mileage is limited to 60,000 miles.

Costs overview 

Strengths Impressive standard equipment list; decent residuals; regular A-Class has a good safety rating 

Weaknesses Very expensive; reliability concerns; won’t be cheap to run

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