2018 Mercedes-AMG GT 4-door spied testing

MERCEDES-AMG’s upcoming Panamera-fighting four-door coupe has been spotted rocketing around the Nurburgring Nordschleife, with a camouflaged prototype hinting at a car that will channel all of the visual aggression of the AMG GT Concept that debuted at Geneva in March – and then some.

Due to be unveiled later this year as a four-door companion to the established AMG GT coupe and convertible, the first-ever sedan to be exclusive to AMG (previous AMG four-doors have been based on regular Benzes like the C-Class, E-Class and S-Class) will have genuine performance cred.

Powertrain details are still a closely-guarded secret, but expect AMG’s 4.0-litre twin-turbo V8 in varying states of tune. If the GT Concept is any guide, a petrol-electric hybrid will be offered as a flagship, potentially boasting as much as 600kW by linking an E63-spec 450kW V8 with a 150kW electric motor.

All wheel drive will endow it with the traction to harness all of that power, and the mammoth brake package spied here gives some indication of the speed this car will be capable of achieving.

A plug-in capability is likely too, allowing it to run exclusively on electric power during less frenetic driving.

Believed to be based on a version of Benz’s MRA architecture rather than the AMG GT’s bespoke chassis (which puts the engine behind the front axle and the gearbox between the rear wheels), the production version of the GT Concept will face off against the Porsche Panamera and Tesla Model S.

Why would AMG use a less exotic platform for its first four-door? Its GT platform is not modular, and was not designed with four seats in mind. Integration of a hybrid drivetrain is also less challenging with the MRA platform, as electrified Mercedes-Benz models on those underpinnings already exist.

Despite all of the camo, it’s obvious the production car will closely follow the template set by the GT concept. A wide grille gives a strong visual link to the AMG GT and GT C, and the flagship will no doubt get the ‘Panamericana’ treatment with bold vertical slats, similar to the AMG GT R’s snout.

Slim tail lights with distinctive LED light bars bookend the car’s rump, and though there’s a pronounced lip spoiler on the car spied here, it’s likely only there to simulate the aerodynamics of a retractable spoiler. A quartet of square-section tailpipes add even more visual aggression to the car’s rear aspect.

Expect to see the production car make its debut later this year, most likely at the Frankfurt Motor Show in mid-September. As a home-ground event, it makes sense Frankfurt will be the venue where AMG gifts itself one hell of a birthday present.