Mercedes-AMG is beefing up its GT sportscar range ahead of 2017 with a new coupe variant of the GT C roadster.

The new GT C coupe slots itself in between the GT S and track-ready GT R with a 4.0-litre twin-turbo V8 been tweaked to 410kW and 680Nm.

That’s 20kW and 20Nm shy of the GT R, but stands 35kW and 30Nm above the current 2016 GT S, and bumps up its top speed by 7km/h to 317km/h.

This cuts only a tenth from the GT S’s 0-100km/h time, mainly because the new GT C coupe also lugs around another 55kg and a total of 1625kg.

2017 Mercedes-AMG GT C coupe

Roadsters are penalised a further 35kg, at 1660kg, and 1km/h of top speed.

Both GT C variants, however, come with 10mm wider rear rubber, with the rear Michelins now measuring 305mm across.

As a result of the wider track another 57mm has been added to the car’s width.

2017 Mercedes AMG-GT-C convertible driving

It’ll come standard with AMG’s interior night package and black chrome highlights on the exterior and inside.

There are also two exclusive ‘magno’ paint finishes; graphite grey and cashmere white.

The new GT C coupe now joins the updated 2017 Mercedes-AMG GT range and is expected here early 2018. The roadster will debut third quarter this year.

Pricing is yet to be announced.