What Car? says...

It seems oxymoronic, doesn’t it? A coupe is something that traditionally has two doors, so adding two more seems to defy convention. But breaking the rules is not necessarily a reason to be poo-pooed, and four-door coupes, like the BMW 8 Series Gran Coupe, have been a big hit ever since the Mercedes CLS burst onto the scene back in 2004. 

Besides, BMW itself has form in defying convention; with the BMW X6, it created the even more mind-distorting coupe SUV concept. It could be argued that four doors on a low-slung coupe is still an agreeable blend of elegance and practicality, while a chunky-looking SUV coupe isn't. So, you could say that the 8 Series Gran Coupe belongs to a rarified club: a car that lets you ‘have your cake and eat it'.