This feels like we’ve come beyond hot hatch or even mega-hot hatch territories now, so I don’t quite know where we are. Mercedes has squeezed hitherto unforeseen power out of a 2.0-litre four-cylinder full series-production engine and installed it into quite a small car to expand yet another niche. Welcome to the world of the 416bhp Mercedes-AMG A45

The A45 hatchback is as fast as small family cars get: a car with a 0-62mph time quicker than an Aston Martin DB11. It’s also available as a small saloon now and will be an estate and crossover soon. The A, CLA, CLA Shooting Brake and GLA are all badged ‘45’ and are, according to Mercedes, ‘the super sportscars in the compact class’, a phrase that feels a bit Google-translated but which describes them well enough. 

This is the hatch. It has five doors so is practical, yet it gets 416bhp and 369lb ft in this S form and will do 0-62mph in 3.9sec. A base 382bhp version is available, too, but we won’t get it in the UK. 

For rivals, look to the Audi RS3 or, if you squint a bit (and on this occasion I think it’s worth it), the BMW M2 Competition, which is short of doors by comparison but an excellent way to spend the £50,000 or so the A45 will cost when deliveries start late summer. 

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A45s roll down the same line and at the same time as ordinary As, although they get wider wings and tracks and some body stiffening brackets – two welded near the front wheel arch, the others bolted around mostly under the body. 

But AMG, Mercedes’ alternative to BMW’s M Division, is, above all else, an engine builder. Its un-woke ‘one man, one engine’ build principle sees that each 1991cc four-cylinder fitted to 45s is hand-assembled by one technician at AMG’s Affalterbach base before being crated to the A-Class production line.

It’s a complex unit in itself, and things get fairly complicated behind it too. The engine drives through an eight-speed dual-clutch automatic gearbox to all four wheels, with the rears via a propshaft which is always turning at the geared speed. Two clutches either side of the rear differential, recent Ford Focus RS-style, distribute power left or right as they see fit – which means under acceleration and cornering, really. In constant-speed cruising they’re pretty idle. 

They can distribute as much torque as the rear axle receives to whichever side they choose – up to 100% of it per side. The system can’t deliberately push more than half of the engine torque to the rear wheels, but in theory the back wheels could be receiving more than 50% of available torque if, say, the body was heavily loaded on the way out of a slippery corner and the fronts were scrabbling. It rarely works like that, though, and, if it does, for no more than a moment.

How does the AMG A45 let the driver access its power?

As you might expect, Mercedes has opted for a lot of drive modes to accommodate all of this. Probably too many, within a cabin that already has rather a lot going on. It’s designed pleasingly, though, with lovely turbine-style air vents that I’m very fond of and a high-resolution instrument pack and central screen. 

But oh my, there’s some tech overload. On the instrument binnacle, pick one of the several options for showing a speedometer on the left, and you’ve still got seven other choices for how the rev counter looks to the right of it. There’s another display in the middle of those two, too. The steering wheel has 17 buttons or levers attached to it, and two of those are multi-function track pads. And yet turning off the lane keep assist is buried in the main centre screen menu. 

I’ll go on. There are five drive modes, or six counting the customisable ‘Individual’ one, which encompasses four ‘AMG dynamic’ modes (how the stability, transmission and four-wheel-drive systems operate), three damper settings, two exhaust modes (although these also vary by drive mode) and two steering weights which you can’t select yourself – some settings are barely heavier than the others. ESC can be on, in Sport, or all off. And there’s a ‘drift mode’ (it doesn’t disconnect the front wheels but puts even more emphasis on an outer rear wheel) and launch control. 

Apparently some markets really like all this. I just wanted to trust what the engineers thought was best and have the relative simplicity of a Alpine A110 or a BMW M2. But no question, it’s effective. The A45 is a bit brittle at low speeds but settles as you get faster, combining good straight-line stability with terrific mid-corner agility and response given that, at 1625kg, it’s relatively heavy for a 4.4m car. The electronics can tweak an inside rear brake on the way into a corner to help turn-in, and as soon as you get on the power it pushes power to the outside rear for a really positive rotation – no need for anything like active rear steer here or, as might be needed in some cars, to give it a bung and lift off. It feels very positive but quite natural. 

Extend the A45 on a track and there’s little understeer, and the rear wheel engagement means you can get on the power early. It’s extremely effective and more involving and adjustable than an Audi RS3. More like a Ford Focus RS, unsurprisingly. 

What's the AMG A45 S like on the road?

The steering’s weight change between modes is pretty subtle. In any it’s medium-weighted, extremely precise and pleasingly responsive. I rather liked it, although in its heavier setting, when there’s lots of torque going rearwards, it felt less inclined to self-centre, so you have to wind the lock off yourself, unnaturally. So off you go to press some buttons and find a better mode, by which time the nice bit of road you’re on has probably ended, which is a shame. 

And then there’s the party piece: genuine AMG levels of shove from a 2.0-litre four-pot. But just as remarkable as the outright speed, perhaps even more so is the way it goes about it. Most heavily turbocharged petrols engines make you wait while the turbo spools before delivering their big slug of torque from low revs. Not so here. 

I think boost pressure is limited at lower revs so the engine feels more naturally aspirated; there’s genuine shove from around 2500rpm but peak torque doesn’t arrive until 5000rpm and peak power at 6750rpm, near the 7000rpm limit. It’s very smooth and very linear and very fast. Depending on the drive mode and exhaust setting (the combination sometimes involves the speakers, too), you might get a muted thrum, a Renault Sport Mégane-like exhaust-and-turbo-rush or a mildly cross growl. The ‘whoosh’ felt most appropriate. The eight-speed dualclutch auto is the best I’ve felt in a Mercedes, fairly zinging through both up and downshifts, and only rarely, on circuit, delaying when you ask for shifts at high revs.

It all makes for a car that feels like it has more in common with a Nissan GT-R than most other normal hot hatchbacks. Not perfect and sometimes annoying, and although a BMW M2 is more two-dimensional, I’d prefer the straightforward rear-driven response of the M car and less bafflement. But if that doesn’t have enough doors or fails to float your boat, then nothing else combines the qualities of the A45.

What Car? New car buyer marketplace - Mercedes-Benz A-Class

Mercedes-AMG A45 S

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