Behold the world's most powerful four-cylinder production cars.

Following a painstakingly long teaser campaign that started last year, the new Mercedes-AMG A45 has finally arrived. It’s not alone at the Goodwood Festival of Speed as the hot hatch is joined by its cooler cousin – the CLA 45. Unlike the previous generation of “45” cars, these new AMGs have spawned an even hotter “S” version offering more power and other upgrades.

With the menacing grille up front with literally a dozen of vertical slats and the quad exhausts at the back, you can immediately tell these cars are a step up from the warm “35” variants. In addition, both feature front canards and a more aggressive rear end with a roof-mounted spoiler in the case of the hatchback and a prominent boot lid spoiler for the saloon. Beefy wheel arches further denote we’re dealing with the range-topping versions of the two model lineups.

Gallery: Mercedes-AMG A 45 4MATIC+ (2019)

The base variants of the A45 and CLA 45 ride on 18-inch alloy wheels as standard whereas the S models are fitted with a 19-inch set. Opt for the flagship version and Mercedes will eschew the grey-painted brake callipers of the base model in favour of larger red callipers with black “AMG” lettering instead of white.

Without a shadow of a doubt, the highlight of these cars is the newly developed turbocharged four-cylinder engine. The 2.0-litre unit codenamed “M139” produces 382 bhp and 354 pound-feet of torque in the standard model and an impressive 416 bhp and 369 lb-ft in the S. Regardless of the one you go for, the engine is hooked up to an eight-speed, dual-clutch automatic transmission and a 4Matic+ all-wheel-drive system.

Gallery: Mercedes-AMG CLA 45 4MATIC+ (2019)

As far as performance is concerned, the base A45 needs four seconds flat to reach 62 mph from a standstill and is electronically capped at 155 mph. You can opt for the AMG Driver’s Package that will unlock a maximum velocity of 168 mph, which is still electronically governed. The A45 S will complete the sprint a tenth of a second sooner, in only 3.9 seconds, and hit the higher top speed right from the start.

When it comes to the CLA 45 and the CLA 45 S, they’re both a tenth of a second slower than the equivalent A45 model due to a slightly higher weight. In other words, the standard CLA 45 does the sprint in 4.1 seconds while the S variant in 4.0s. Top speed is identical to the A45 models.

Regarding the drift mode that has been extensively teased, it’s standard on the S model and optional for the non-S cars. The tail-happy nature of the two cars can be accessed by enabling the Race driving mode, turning off the ESP, and switching the transmission to manual mode.