Mercedes-AMG A45 W177

The W177 A45 is built around the M139, hand-assembled at Affalterbach under AMG's one-man-one-engine rule. It is a closed-deck 2.0-litre four, turned 180 degrees so the twin-scroll turbo sits against the bulkhead and the intake faces forward. The A45 makes 387 PS. The A45 S makes 421 PS (416 hp) and 500 Nm, which made it the most powerful series-production four-cylinder on sale.

Mechanically the rear axle is the story. AMG Performance 4MATIC+ uses AMG Torque Control: two electronically controlled multi-plate clutches, one for each rear driveshaft, so torque can be split side to side as well as front to rear. That is what makes drift mode possible, and it is standard on the S. The gearbox is an eight-speed dual-clutch. The S has 360 mm front discs with six-piston calipers.

Against the W176 this is a different kind of car. The first A45 was front-biased with a single rear clutch. This one can send more torque to one rear wheel than the other and rotate on the throttle. It sits above the A35, which uses a simpler engine and a simpler rear axle.

Where it places in the lineage: probably the end of it. AMG has said the M139 will not be carried into Euro 7, and a Final Edition was announced in 2026. It was never sold in the US, which got the CLA 45 instead.

• Final Edition (2026)
  Run-out A45 S with special paint, yellow detailing and an aero package. Not limited by number, and mechanically standard.

Never sold in the US, which got the CLA 45 instead; the figures here are European. There are two outputs: the A45 with 387 PS (382 hp) and 480 Nm, and the A45 S with 421 PS (416 hp) and 500 Nm. The figures shown are the S. Drift mode is standard on the S and part of the AMG Dynamic Plus package on the A45. The M139 is turned 180 degrees, with the turbo at the bulkhead and the intake at the front. AMG has said the M139 will not be carried into Euro 7, and the Final Edition was announced in 2026 as the run-out car; Mercedes had not given an end-of-production date when this was written.