Mercedes A45 AMG

The all-wheel-drive A45 AMG is a blisteringly quick car. In fact, you’ll find it hard to believe there’s only a 2.0-litre engine under the bonnet. A vast array of changes to the A-Class’s chassis improves the handling, too. And while the A45 AMG may not be the last word in driver involvement, to many the incredible pace will be all that matters. It does cost £7,275 more than the more engaging BMW M135i, but its straight-line performance is incredible.

‘The Beast’ – that’s the nickname AMG’s engineers gave the new Mercedes A45 AMG during its development. And within just one minute behind the wheel it’s pretty obvious why.

Under the bonnet is a 2.0-litre turbo that produces 355bhp. That’s 178bhp per litre – more than any other production car in the world. This is the very first time AMG has built a four-cylinder engine, but you’d never know as Mercedes has managed to make it 39bhp more powerful than the straight-six in the BMW M135i, despite having just two-thirds of the capacity.

AMG has a one man, one engine policy and the 2.0-litre in our car was hand-built by Jerome Wachholz. He’s done a good job, because although this early right-hand-drive example was barely run in, it proved to be way faster than Mercedes’ claims.

Watch the Mercedes A45 AMG take on the CLS63 AMG in a drag race

The official figures say the A45 AMG will go from 0-62mph in 4.6 seconds with launch control. This is engaged by putting the stability control in sport mode, the gearbox in manual mode, selecting drive using the special AMG selector and holding down both solid metal steering wheel paddles to engage ‘race start’.

In reality, however, it’s even quicker than that. In our hands, it went from 0-60mph in only 4.1 seconds. And to find out just how fast the car is over a standing quarter mile, we raced it against a CLS 63 AMG Shooting Brake. You can see what happened by watching the video above.

The engine isn’t only good when it’s being thrashed, though. Peak torque of 450Nm arrives from 2,250rpm thanks to a twin-scroll turbo, so there’s hardly any delay between pushing the throttle and feeling the thrust, but still an intoxicating top-end rush. If we have one complaint, it’s the noise. It’s by no means bad, and does make a nice ‘thrump’ when you change up a gear, but overall the A45 doesn’t quite sound as fruity as you’d expect of an AMG.

To be fair, though, our car featured the standard exhaust; an optional sports system apparently makes the A45 a lot more vocal, with pops and crackles on the overrun.

Obviously it’s the engine that dominates the A45 experience. But AMG has also extensively overhauled the rest of the A-Class. Inside, there’s a carbon-look facia, red air vent surrounds and a sports steering wheel, while outside there’s an AMG styling kit and 18-inch alloys that hide larger, more powerful brakes.

AMG has also upgraded the A-Class’s seven-speed twin-clutch auto box – which now gets more tactile metal steering wheel paddles and that unique gear selector. Shifts are now slicker than before and it gets less confused in auto mode, too, although it’s still not as good as an Audi S3’s unflappable dual-clutch transmission.

Like its Audi rival, the A45 has all-wheel drive, and the 4MATIC system can send up to 50 per cent of the engine’s torque to the rear wheels. This helps boost away-from-the-line acceleration and improves traction when exiting corners, allowing you to get on the power sooner.

There are also new dampers, springs, hubs, axles and anti-roll bars. These changes have improved not only the handling but, surprisingly, also enhance the ride quality. Of course, you are naturally more accepting of a firm ride given that this is a performance-focused car – but there’s also an added compliance that’s sorely missing in the regular A-Class.

This means you can feel what’s going on beneath you through the AMG sports seats. This is handy, as you don’t get so much communication from the steering wheel. Even though AMG has reworked the steering set-up, it still doesn’t have the immediacy or feel of a BMW M135i’s steering.

The A45 is never quite as adjustable as the rear-drive BMW, either, although you can get the car to move around if you’re aggressive. You can disengage the stability control if you really want to play the hooligan, but as soon as you touch the brakes it automatically re-engages.

Does this really matter? It will depend what you want. If you wish to cover ground quickly and in all weathers, the A45 is ideal. What’s more, when you consider its straight-line performance, the £38,000 price isn’t as steep as it first seems. If you want a truly rapid point-to-point car that still feels playful at the limit, the Beast is hard to beat.