Light Front, Runs and Drives, Airbags Good., , Though the XJ shares its direct-injection power plants and six-speed automatic transmission with the XF, Jaguar says the larger XJs swift sprints come courtesy of a similar aerodynamic drag coefficient and lightweight aluminum construction. Mechanical features include:, , Standard 5.0-liter V-8 rated at 385 horsepower, Supercharged 5.0-liter engines make 470 hp in the Supercharged trim level and 510 hp in the Supersport, Standard air-spring suspension that varies firmness as conditions dictate