302bhp Mercedes-AMG A35 priced from £35,580

Key engineering attributes of the AMG-tweaked powerplant include uniquely tuned twin-scroll turbochargers with reduced back pressure, reprogrammed Camtronic variable valve control, special liners that contribute to conically shaped cylinders and a bespoke exhaust system with an automatically controlled flap that modulates the exhaust note depending on the driving mode.

With 302bhp at 5800rpm and 295lb ft of torque between 3000rpm and 4000rpm, the transversely mounted engine delivers 81bhp and 77lb ft, more than the less heavily tuned version of the M260 unit used by the A250 but 74bhp and 55lb ft less than the more highly strung M133 engine used by the A45 4Matic.

Of the keener, premium-brand competition, the rear-wheel-drive M140i’s turbocharged 3.0-litre inline six-cylinder engine delivers 335bhp and 369lb ft and the four-wheel-drive Audi S3’s turbocharged 2.0-litre four-cylinder offers up 306bhp and 280lb ft. 

Drive is channelled to all four wheels through a seven-speed dual-clutch gearbox featuring AMG’s own Speedshift software that is claimed to provide more rapid shift times and more intuitive upshift and downshift characteristics than the standard software package, as used by the A250.

As well as offering both manual and automatic modes, the in-house-produced gearbox also includes a Race Start function for improved off-the-line accelerative performance as well as steering-wheel-mounted paddles as standard.

Allied to the A35’s gearbox is a heavily revised version of the 4Matic four-wheel-drive system used by the first-generation A45. It boasts variable distribution of drive, from front-wheel drive only to a 50:50 apportioning to the front and rear axles, via an electro-mechanically operated multi-plate clutch integrated into the rear axle assembly.

The driver is able to choose between five different driving modes via an AMG Dynamic Select controller: Slippery, Comfort, Sport, Sport+ and Individual. The Slippery mode, a new development that is also planned to appear on the new A45 when it is launched in 2019, is programmed for wet road conditions, with reduced power and torque and earlier upshifts in automatic mode. 

Also new is a so-called 'gliding' function. It allows the driver to choose between 'reduced' and 'moderate' settings for differing engine braking characteristics while coasting on a trailing throttle within the Individual driving mode.

With the Sport+ mode and Race Start function engaged, the A35 4Matic is claimed to accelerate from zero to 62mph in 4.7sec and reach a top speed limited to 155mph. Combined cycle consumption is put at 38.7mpg, equating to average CO2 emissions of 167g/km on the recently superseded NEDC (New European Driving Cycle). 

This gives the A35 4Matic a slight edge over the M140i and S3, which are claimed to accelerate to 62mph in 4.8sec and 5.3sec respectively, in outright straight-line performance. 

To cope with the added performance potential brought on the A35 4Matic’s new drivetrain, Mercedes-AMG has stiffened the bodyshell of the A-Class hatchback on which it is based with the addition of a so-called 'shear panel' underneath the engine. The aluminium structure is bolted to the existing steel body shell and, in combination with two additional diagonal braces, is claimed to provide added torsional stiffness to the front end.

The stiffened body structure supports a MacPherson strut front suspension. It uses a newly developed aluminium carrier and radially bolted steering knuckle that AMG claims reduces the unsprung masses and provides more sensitive response to the system used by the A45 4Matic. The rear suspension is based around the four-link system used by upper range A-Class models, with three transverse arms and the trailing arm, the wheel carrier and bearings shared with those of the A45 4Matic. 

Passive dampers are standard, though buyers can option the new entry-level AMG model with an adaptive damping system that provides three different levels of stiffness. The electro-mechanical steering uses variable assistance and a more rigid mounting than the system used by other new A-Class models. The brakes, meanwhile, use four-piston monoblock calipers and 350mm vented and perforated discs up front and single piston calipers and 330mm discs at the rear. 

The A35 4Matic builds on the sharpened appearance of the fourth-generation A-Class with a unique grille, more heavily structured front bumper, standard 18in alloy wheels, wider sills, bold tailgate-mounted spoiler and a new rear bumper featuring a prominent diffuser element bookmarked each side by blackened round tailpipes.

Inside, the standard A-Class interior has been reworked with unique upholstery for the seats an AMG steering wheel with touch-pad controls and AMG-specific graphics for the digital instruments, including a Supersport mode with a large central round rev counter.

Other new features include AMG Track Pace as part of the MBUX infotainment system. It permanently records data during track driving, enabling the driver to analyse a range of information including acceleration, braking and lap times. 

A series of options packages are offered on the new car, including the £2595 AMG Style package that adds an aerodynamic bodykit and 19in alloy wheels.