Even if its future is not guaranteed, Cadillac's XLR, built on the Corvette's platform, continues to impress if only because of its sharp angles. This coupe becomes a convertible at the touch of a button, but one must travel light! The basic version comes with a 320 horsepower V8 engine, while the sports model, the XLR-V, also gets a V8 engine, boosted to 443 horsepower.