The second-generation BMW Z4 Roadster grew in size compared to the car it succeeded and adopted a very different nature, too. It became a more relaxed and much less demanding kind of car, but also a less exciting one. The folding hardtop roof made it both swooping coupe and stylish roadster, although the roof’s inherent weight penalty will be impossible for the keenest drivers to overlook. A wide range of engines should satisfy all tastes and budgets.