The midsize X5 is the brand's bestselling utility vehicle. It's also the most spacious, and the one that offers the most powertrain choices. Aside from turbo six- and eight-cylinder gasoline engines and a turbo-diesel six – with power ranging from 255 to 445 hp – there’s also a high-performance X5 M that punches out 567 hp. And for 2016, the X5 xDrive40e has been added, a plug-in hybrid that serves up 313 combined hp and an EV range of about 30 km.