2018 BMW 8-series Spied: A Big, Bold Luxury Two-Door What It Is: BMW’s upcoming 7-series-based 8-series coupe, covered in camouflage and penned in among other BMW prototypes. Expected to be larger than today’s two-door 6-series (the six can also be had in four-door Gran Coupe form), the 8-series will serve as BMW’s flagship coupe, just as its eponymous forebear did…