Mercedes-AMG CLA45 S Coupe review: The pocket-sized AMG maniac comes with 421hp and goes from 0-100km/hr in four seconds

By Daryl Lee 16 March, 2021

The Mercedes-AMG CLA45 S Coupe is a storming little saloon with the world’s most powerful series production four-cylinder engine

The Mercedes-AMG CLA45 S Coupe (good lord, what a mouthful and not to be confused with the Mercedes-AMG A35 Saloon… it’s complicated, don’t ask) is home to the world’s most powerful mass-production four-cylinder engine with a borderline lunatic 421hp/500Nm, from only a two-litre displacement.

Let that number sink in for a moment. From a horsepower-per-litre standpoint, it’s more power-dense than the four-litre, twin-turbo V8s Mercedes-AMG has on its flagship GT63 S 4-Door Coupe

That ‘just’ has 159.8hp per litre of engine displacement, versus the 210.5hp in the CLA45 S Coupe here. 

The performance of said engine is just as thumping as you might imagine. A firm prod of the right pedal results in a rising cacophony of turbocharger whistle, a guttural roar from the motor and a sensation of achieving what I can only describe as an appreciable fraction of light speed. 

In a word, the engine is brutal, and it gives the impression it has deep, deep reserves. Reserves that you’ll barely even scratch on public roads (with pesky things like cops, speed limits and the all-seeing eye of a million dashboard cameras), let alone a closed race track. 

So, you might be wondering, what the point of a pint-sized pitbull of a car like the CLA45 S Coupe might be. Harnessing all (if not most) of its power is beyond the reach of most mortals, the ride can get obnoxiously firm, it costs a pretty penny at S$315,888, and let’s face it, is still based on one of the junior members of Mercedes-Benz’s vast family tree.

It depends on who you ask, really. If you ask Mercedes-AMG, the purpose of the CLA45 S Coupe, and all of its other ‘45’-badged compact cars (CLA45 Shooting Brake, A45, GLA45 and upcoming GLB45) is to reach a more youthful audience owing to their lower price points, filling the once-yawning gulf between a regular Mercedes-Benz car and an AMG model. 

If you ask me, I’d say it’s to debunk the long-held myth the Germans don’t have a sense of humour. A hugely powerful engine stuffed into a small car is always hilarious, and the CLA45 S Coupe is a proper barrel of laughs. The joy it has is quite simply infectious, and it’s difficult to drive it and not have a stupid grin plastered on your face. 

The engine’s aforementioned savagery aside, the CLA45 S Coupe is about as close to an old-school turbocharged car as they come, in that it eschews the modern paradigm of linearity for a gutsy sucker punch once the engine hits about 3,000rpm or so. 

Sure enough, this on-off nature, coupled with the low-speed jerkiness of the eight-speed dual-clutch transmission and overly firm ride makes driving the CLA45 S Coupe sedately a near-impossible task. Tougher even than exploiting its full potential, I’d reckon. 

And that perhaps is the crux of the CLA45 S Coupe. It’s a downscaled version of a larger Mercedes-AMG car, with all the trappings and pitfalls that entails. Which almost makes the S$300,000 asking seem like an absolute bargain, with virtually all the performance of something like the GT63 S 4-Door Coupe at around half the price.  

Sure, it may not have the snob appeal of a bigger car, but when you’re having this much fun, it’s a little hard to care.