But i believe he tried to design the vents to evacuate a little bit of heat from the engine bay. One thing I would be a little concerned about would be rain running down into the backwards NACA ducts and into the engine bay when the cars sitting and its raining. I guess you can tape up the ducts, but then you'd have a nice little puddle of water sitting there. Hopefully he keeps his Z garaged. Overall it looks pretty good though, i like the center vent.