Spoon may sponsor the car but that doesn't mean the car uses all Spoon parts. This is true from the lowest end of motorsport to the top. For instance in Indycar HPD makes the engine but ECU is all from Cosworth or McLaren. It's a lot easier to give certain components of your car (like the ECU, exhaust, and suspension systems) to someone else to work on while you concentrate on your own thing. In this case it looks like Spoon did most of the engine and maybe the chassis work.