Companion to the luxurious XLR roadster is the XLR-V, a supercharged dynamo intended to challenge the best from Mercedes-Benz, Jaguar and Porsche. On paper, the XLR-V certainly meets all the criteria, with a 443-horsepower supercharged V8 engine, a sub five-second zero-to-60-mph acceleration run and a six-figure window sticker. On the road, however, the story is not so clear. That's because the XLR-V's Corvette-derived chassis does not quite deliver the polish one experiences when driving a Jaguar XK or BMW 650i. And, while the Cadillac name is certainly making a comeback, in most circles it does not match the images of its European rivals.