Average fuel consumption is put at 20.0mpg for both models for combined CO2 emissions of 319g/km on the WLTP test cycle.
The basis for the GT is a newly developed body structure shared with the SL. It uses a material mix consisting of aluminium, composite fibre materials, magnesium and steel.
The styling draws heavily on the first-generation model, with a traditional cab-back profile dictated by a long bonnet, curved roofline and angled liftback tailgate.
Among the aerodynamic developments is a so-called “active air control system” within the grille to alter the flow of air to the engine bay, a carbonfibre element within the underbody which lowers by 40mm to create a wind-cheating Venturi effect and a retractable rear spoiler that automatically deploys at 50mph and offers up to five different wing angle positions.
Buyers can also option the new GT with an aerodynamic package. It includes small winglets on the outer sections of the front bumper and wheel arches, as well as a fixed rear wing.
Both the 55 and the 63 have standard 20in wheels, shod with 295/35 (front) and 305/35 (rear) profile tyres. Buyers can specify f 21in wheels as an option.
At 4728mm in length, 1984mm in width and 1354mm in height, the new coupé is 182mm longer, 45mm wider and 66mm taller than the first-generation GT. It also has a wheelbase that is 70mm longer than before, at 2700mm.