Numbers are a funny thing, and in the realm of BMW nomenclature, the X5 SUV is actually a bigger and more practical barge than the sloped-roof X6. In many ways, the X6 behaves like a thick 3-series in high heels. Powered by either a 335-hp inline-six engine (40i) or a feistier 523-hp twin-turbo V-8 (M50i), the X6 deploys power with the same smoothness of shaving cream. For more power, seek the X6 M with up to 617 horsepower (reviewed separately). Although the X6’s exterior proportions look misshapen, the interior is elegant and functional. The fashionably slanted roof sacrifices some headroom and storage space, but those who prefer its striking looks above all else are unlikely to mind its higher price tag over the X5.