The performance variant of Benz's all-new SUV has been spotted on the tarmac, wearing new wheels and headlights.

Photographers have snapped images of what is believed to be an early prototype for the Mercedes-AMG GLB35 again this week, indicating the upcoming boxy crossover should be getting a go-fast version.

Compared to the development vehicle spotted in January, this prototype is wearing new alloy wheels, though the heavy camouflage appears to be the same.

We can see the beefed up bumpers, Panamericana grille and deeper side skirts, while the large circular tailpipes down back lead us to believe this will be badged '35' as the design is consistent with the new AMG A35.

We can also see bigger brakes peeping through from behind the wheels, along with what looks like to be the higher-grade LED light units front and rear – the previously spied prototype had halogen headlights.

Being an AMG 35, the GLB35 should be powered by a 2.0-litre turbocharged four-cylinder petrol engine, making around 225kW of power and 400Nm of torque sent to all four wheels via a dual-clutch automatic.

Expect a 0-100 time of around 5.0 seconds, and a performance-tuned 4Matic all-wheel drive system that can send up to 50 per cent of torque to the rear axle.

Considering the standard GLB hasn't even be revealed yet, the AMG version could be up to 12 months from its debut.

Speaking of the standard model, the boxy crossover is likely to be the more practical small SUV alternative to the next-generation GLA, competing with the likes of the Audi Q3, BMW X1 and Volvo XC40.

There's even talk of a seven-seat version, though it's not confirmed at this stage nor do we know if the three-row variant would get the AMG treatment, either. Stay tuned for all the latest, and click on the images for the full gallery.