The X6, one of BMW's recent forays into SUV territory, is a tallish fastback that the company calls a sports activity coupe. With seating for four, it's basically a midsize SUV with four doors, extroverted styling and a choice of two powerful engines. The X6 competes roughly with the Porsche Cayenne and Mercedes M-Class. BMW's xDrive all-wheel drive is standard, and the X6 comes in two trim levels: the xDrive35i and xDrive50i. Both models seat four, and the xDrive50i's V-8 will propel the SUV from zero to 60 mph in just 5.3 seconds.