2009 Jaguar XFRTop Cat: New 510-hp Leaper is the Best of the BreedBy Mike ConnorYou know you're suffering from hp-war battle fatigue when your first reaction to the news the Jaguar XFR's all-new, supercharged 5.0L direct-injection V-8 develops 510 hp is a faintly disappointed "Oh..." It might outgun the 500-hp BMW M5 and the 507-hp Mercedes-Benz E63 AMG, but it comes up short against Cadillac's