As Jaguar's flagship, the XJ charms buyers with superior luxury equipment and, of course, a prestigious legacy. The available engines range from the 3.0-litre 340-horsepower supercharged V6 found in the XJ and XJ L, to the impressive 5.0-litre 470-horsepower supercharged V8 that powers the XJ Supercharged to the most powerful, a 5.0-litre 550-horsepower supercharged that propels the XJ R, which is the sportiest of the lot.