The Jaguar XK has, for years, been a curvaceous bundle of sinew, calibrated to exude understated beauty. Its newest iteration, though, the Jaguar XKR-S, is the bad boy of the lineup, a 186-mph missile that hurls thunderclaps from its exhaust. Thus, its bodywork required a dose of aggression. But how do you infuse the XK with go-fast attitude (and high-speed stability) without ruining it? By adding aero pieces like the twin nacelles ahead of the front wheels, blacking out the trim, and offering colors like "French racing blue," which is roughly the hue of police lights. The XKR-S is also the first Jaguar production car to wear a fixed carbon-fiber rear wing. And it wears it well. [From $132,000;]