[wildman10]

Thanks. I have, though, already measured static pressures at all the relevant exit points (bonnet, fender/wing upper surface, and at the vents behind the fenders/wings that are primarily for styling). My write-up contains more information and the attached images show some results at the bonnet/hood centreline and an RX8 with the carbon bonnet/hood that I inherited with my car (the main vent is as far forward as the car structure allows and the rear side vents are at the rear of the engine bay).

I cannot get any meaningful pressures inside the wheel well with my simple tube and Magnahelic gauge system as the turbulent air makes the readings fluctuate wildly.