It looks like the 2008 Jaguar XJ sedan will be getting a few styling updates as it undegoes cold weather testing in England. Although most of the bodywork on this prototype appears unchanged, the front airdam has a slightly different shape compared to current models. It's also clear that this test car is wearing the side vents currently used only on the top of the line Portfolio model. Changes in back look as though they'll be nothing more than a slightly reshaped bumper valance.