RUF and Magna Steyr are technical partners, yes, and the car actually has a Porsche engine.
But you still haven't said who actually builds the bodies.
Although you're an Expert now so technically can't participate in Rookie puzzles any more, this one is really your puzzle so I'll keep it locked for you to get your final Rookie point.
Let me know your answer by PM if you find you can't post on the Rookie board!