In theory, the Mercedes-AMG CLA 45 should be exactly the same to drive as the rabid and deeply excellent Mercedes-AMG A 45. Because despite its sweeping new junior Mercedes-Benz CLS lines, the Mercedes-Benz CLA is actually identical to the A 45 beneath the skin.
That means originally you got the same 355bhp, 2.0-litre turbocharged four-cylinder engine as the A 45, the same crisp but direct electric power steering, the same seven-speed dual-clutch automatic gearbox, even the same spring rates for its new strut and multi-link suspension system.
Then in 2015, Mercedes-AMG decided to turn up the wick of the engine, which saw not only the A 45 suddenly produce 375bhp, but also the CLA 45 and GLA 45. All this was in direct response to Audi's audacious attempt to make the RS3 the most powerful hot hatch on the market.
Despite the CLA weighing a piffling 30kg more than the A 45 AMG, Mercedes even makes the same performance claims for its two four-wheel-drive, entry-level AMGs.
The CLA 45, just like the A 45, will hit 62mph from rest in a claimed 4.2sec thanks in part to its 'race start' launch control system, and it’ll reach the same 155mph limited top speed, having hit 100mph in approximately 11.0sec en route, making a delicious noise in the process – particularly if you go for the optional AMG Performance Exhaust.
So although a dinky little four-cylinder coupé may not sound like the kind of car that would normally wear Mercedes' most prized of badges, times are a-changing, even at AMG. And in the process, the raw performance of the cars is suffering not one bit.