The new Mercedes-Benz GLA45 AMG has been revealed in production form ahead of its debut at the Detroit Motor Show.

The pinnacle of the GLA range, the GLA45 AMG is powered by the same turbocharged 2.0-litre four-cylinder engine as the A45 AMG and CLA45 AMG, and in its new home it continues to produce an astonishing 360hp at 6,000rpm and 450Nm of torque from 2,250-5,000rpm.

Mercedes refers to it as the most powerful series-production four-cylinder turbo engine in the world, but what’s more surprising is the engine’s environmental performance.

While the GLA45 AMG can accelerate from 0-62mph in just 4.8 seconds and on to an electronically-limited 155mph top speed, it can still achieve 37.6mpg and emits just 175 g/km of CO2.

Mercedes have worked to tune the GLA45’s aural performance, too, with a flap in the rear exhaust silencer that opens and closes depending on engine load.  A further performance-tuned exhaust is available as an option.

The engine is mated to AMG’s Speedshift DCT seven-speed dual-clutch transmission with Manual, Sport, and Controlled Efficiency modes, and this drives all four wheels through AMG’s 4Matic four-wheel drive system.

In normal driving, the system distributes power to the front wheels only for maximum efficiency, but can send up to 50% of torque to the rear wheels as conditions dictate.

The suspension has been specially tuned for the GLA45, with thicker anti-roll bars, optimised spring and damper rates, and stiffer steering knuckles.

The brakes have similarly been upgraded, with cross-drilled discs all round and grey-painted calipers poking out from behind 19-inch five-twin-spoke light alloy wheels, with 20-inch wheels available as an option.

Accentuating the sporting theme are the AMG front apron, twin blade grille, large air intakes, twin tail pipes and rear diffuser.  An optional aerodynamic package adds a larger front splitter, additional aero tweaks and a large rear spoiler.

The interior, meanwhile, features AMG sports seats in Artico (a man-made leather-like material) and microfibre with red stitching and red seat belts.  Brushed aluminium is dotted around the cabin, with various carbon-fibre treatments available as options.

UK prices and specifications are yet to be announced, but sales are expected to begin in the spring.