2018 Mercedes-AMG GLC 63 | spy pics

A lightly camouflaged prototype of the Mercedes-AMG GLC 63 Coupe has been caught testing at Mercedes' cold weather test facilty in the Arctic Circle. A looming rival for Porsche's Macan Turbo and Audi's SQ5, the hardcore flagship of the GLC Coupe line-up is due to make it global debut late this year, with Australian on-sale scheduled for early 2018.

The modest disguise obscures a face likely to mirror its C 63 Coupe sibling with blacked-out mesh grille and silver doubled louvres – different from the GLC 43 Coupe it sits directly above, which features a chrome-studded ‘black diamond' grille. The C63 Coupe's twin-decked splitter and large lower air-intakes, could easily be adopted, too.

Camouflage on the back of the car almost certainly hides a bumper similar to the C63 Coupe's, but what's not hidden is the quad exhaust – identical to its car cousin and different from the GLC 43 Coupe's rounded tailpipes.

We expect GLC 63 customers will want a combination of ample space for passengers/cargo and performance similar to a sports car.

The test vehicle is wearing mismatched 20-inch snow shoes - five-spoke alloys with black and high sheen finish (a GLC Coupe range option) at the front, and five-point star rims (similar to those seen on the current C-Class) at the rear; the latter likely to be a new design which will arrive with the GLC 63 Coupe.

Only the top-shelf S-spec C 63 sedan, wagon and coupe is offered Down Under, powered by a 375kW/700Nm version of AMG's 4.0-litre twin-turbo petrol V8, and the same approach is likely for the GLC Coupe.

While not confirming local specification, Mercedes-Benz Australia's Jerry Stamoulis told CarsGuide the GLC 63 Coupe is due to arrive in Australia in early 2018, adding that, "There will be a significant difference in design between the 43 and 63, and we expect GLC 63 customers will want a combination of ample space for passengers/cargo and performance similar to a sports car."

Does a bruising SUV Coupe like the GLC 63 get your adrenaline flowing? Tell us what you think in the comments below.