SPY PICS: AMG GT sedan hits the road

It may have the word "concept" in its name but, as you can see from these first spy shots, the exterior design of AMG's all-new four-door GT show car is pretty much what you'll see romping around Europe, the USA and indeed Australia in 2018.

Making its debut at the 2017 Geneva motor show, the AMG GT sedan concept's flowing roofline, long bonnet and curvy retro-influences will be gracing Mercedes-Benz showrooms before long.

Just don't expect the trapezoidal exhaust tip though.

"That's for the show car," laughed Mercedes-Benz chief of design, Gorden Wagener, "but other than that, I would say it's 90 per cent production ready."

AMG's recent success, falling just shy of 100,000 sales annually, has given the company a mandate to take risks, to be more radical. So it's pushing the boundaries of not only performance – with cars like the AMG Project One – but also design, and that's exactly what's occurred with its new four-door GT production car.

"Proportion is important, so it sits proud on the rear, has a long Mercedes hood and the Pan Americana face, a new signature face for AMG is in the front," Wagener told motoring.com.au during a one-on-one interview.

"The coke bottle shoulders in the rear are GT signature graphics too. It's the complete DNA of the GT coupe brought to four-door, which I think is more radical than anything else you see out there."

Mercedes' chief designer noted that one of the most impressive things about the design is actually inside – headroom – which he describes as "significant" for all occupants. "I can sit in the back, taller people than me even," said the six-foot-plus German.

Although AMG chose to keep the interior design of the show car under wraps for its global premiere in Switzerland, motoring.com.au has learned the cabin will combine luxury and sports in a new way, and it will have plenty of the back-seat technology to take the fight to Porsche's all-new Panamera.

Hartmut Sinkwitz, the head of interior design at Mercedes-Benz, said the interior design is "almost finished" and borrows heavily from the new-generation E-Class. That means it will probably also have a lot of self-driving tech.

"We will have an interior that very much fits into the E-Class family," said Sinkwitz. "There will be some things that you will be familiar with and some things that will be totally new.

"But it will be a very, very sporty and luxurious interior," he assured.

AMG has already confirmed the production version of the four-door cruiser/bruiser will be on sale in 2018, initially propelled by a 4.0-litre biturbo V8 then augmented by a hybrid set-up, the latter good for a mind-melting 600kW of power, or 800hp.

Ola Kallenius, Mercedes-Benz chief of research and development, calls the curvaceous new AMG GT four-door sports car "a predator" that rips to 100km/h in less than three seconds.

But for many well-heeled car buyers, this expensive, exclusive grand tourer from AMG will be all about a striking, somewhat risky new design that pushes the brand in a daring new direction.