BMW’s first SUV was the X5, and it remains the biggest of the bunch, offering seating for five, all-wheel drive and a range of straight-six and V-8 engines. Built in the U.S. at BMW’s Spartanburg, South Carolina plant, the BMW X5 has been on sale in the U.S. since 1999. Its primary competition is the Mercedes M-Class, Audi Q7, Porsche...