i think same chassis and some parts sharing - materials used/design wise are all by Mazda. they did the same with the EZ-6.

i think Mazda's war chest empty already, spending all their monies on the CX-*0 series and the development of their new inline 6 + gearbox. if you follow, i think they are going to spend whatever little that is left on the development of their new Skyactiv-Z engine.

let's hope Mazda's engineers don't drive their company to the ground.