FOR MORE ABOUT THE JAGUAR XF-R: www.edmunds.com After seeing prototypes running around England, we figured it was only a matter of time before we would catch up with the 2010 Jaguar XF-R in Death Valley. Running solo in a new shade of silver, this high-performance version of the standard XF sedan is designed to give Jaguar a true super sedan to compete with the likes of the BMW M5 and the Mercedes-Benz E63 AMG. This latest XF-R prototype wears many of the same upgrades as the earlier test mules. The deeper airdam up front is the most obvious upgrade, as the air intakes appear slightly larger than those on the standard model. It also looks like a pair of hood intakes have been added as well. There are new, more aggressive rocker-sill extensions as well, although the wheels appear to be the same set of optional 20-inch items available for the standard XF. In back, a set of quad tailpipes is another obvious tip-off to this XF’s high-performance engine hardware. So what’s under the hood? All indications point toward a new supercharged 5.0-liter V8. It’s an all-new engine that will filter down to the entire Jaguar lineup in one form or another, not to mention Land Rover’s upcoming SUVs. In the XF-R, it will likely produce around 500 horsepower, a number that will put it right in line with the rest of the luxury super-sedan crowd. Expect to see the official debut of the 2010 Jaguar XF-R early next year, with sales beginning by the spring of 2009.