I did see one yesterday on the Autobahn. It was together with 2 992 mules. Can not say anyhting about the engine sound. 

Finding a GT3 engine in this car would mean the world. This car would instantly be top of the most adorable Porsches list. . 

And - if this is true that they take all isolation out and make it lightweight they rather would call it "Speedster" instead of "Spyder".