The next-generation 2015 Mazda MX-5 roadster has started its customary development cycle – pounding the Nurburgring – as shown in this set of photos taken by our European spies. There’s nothing much on show, as the test mule wears a heavily adapted body of the current model.

What is apparent is that the new model is set to grow both in length and width, as the mule’s stretched doors and widened wheelarches show. Fret not, however, as new weight saving technologies will likely keep the next MX-5 close to its current weight of just over 1,000 kg.

The same platform will also be used as a base for the Alfa Romeo Spider revival project. Only around 40% of the parts will be shared between the two models (well below the 60% commonality in typical joint venture projects), all of which will be hidden under the skin.

The Mazda is likely to stick to conventional naturally aspirated SkyActiv engines, while Alfa prefers its own small-capacity turbocharged motors. No question, then, that each roadster will have its own brand and heritage-specific looks and dynamics. Mazda or Alfa, which would be your pick?