The concept is rumored to be presented as a design study, previewing a production model that will follow the M8 Coupe.
The four-door M8 is expected to be presented as a design study, perhaps short on final details, according to BMW Blog.
Previous rumors suggest the standard 8 Series Gran Coupe could start with the 840i, powered by BMW's 3.0-liter turbocharged inline-six. The family is also believed to include an 850i with a turbocharged 4.4-liter V8, while an M860i could borrow the M760Li's V12 and xDrive all-wheel-drive system.
An M8 Gran Coupe would likely be powered by an even more powerful 4.4-liter twin-turbo V8, presumably with significantly more than 600 horsepower and capable of launching to 60 mph in about three seconds.
A sleek four-door M8 is not expected to arrive on the market until the M8 Coupe goes on sale late next year or in 2020.