Running With the Big DogsBy Alistair Weaver, European Editor EmailDate posted: 02-24-2009The 2010 Jaguar XFR sneaks up on you. You have to drive with one eye on the speedometer, cross-checking your perception of speed with the reality displayed in black, white and red. The XFR is not a raw-edged racing sedan; it's a supercharged 510-horsepower express that baits the BMW M5 with its sheer