With a rumoured 500-plus bhp horsepower, Jaguar's upcoming XF-R was spied in the southwestern part of the United States. Powered by a supercharged 5-litre V8 and riding on unique 20-inch alloy wheels, Jaguar isn't doing too much to hide the larger air intakes, a discreet spoiler and quad exhaust. We're expecting an official debut early next year.