2006 BMW Z4 M Coupe vs. 2006 Porsche Cayman S

Two used-to-be roadsters aim for the hearts of purist drivers. The tradition of sports-car automaking in recent history has been to turn out a roadster, wait until sales slip, then produce a hardtop to pick up the slack. To the nonenthusiast driver, the idea of turning a perfectly good convertible sports car into a hardtop coupe must seem as pointless as the plot of the film Snakes on a Plane.