Not sure how this would work in THIS setup, but I do know Robains question applies to the airflow in the N/A Exige engine compartment.Not sure I buy your argument...
the flow from the roof scoop will also be under pressure from airflow being forced in at speed.
Total effective outlet area of the IC (taking out all the area blocked by the bars and fins, etc.) is still going to be greater than the area of the roof scoop.
This could further be assisted by some fans pulling through the IC
The first time I drove my 06 Exige with the top off at speed, I reached up to the 'mail slot' opening...which indeed is open on the 06 even though the roof scoop is not open, and at 60 MPH air was actually being forced out of the roof scoop AGAINST the oncoming air, presumably from airflow through the side scoops, from underneath through the NACA ducts, and however the air was actually moving through the rear mesh on the deck lid.
I actually pointed this out when the S's first came out, and folks posted that because the scoop system on the S is closed as air is directed through the IC, it wouldn't be an issue. But deliberately directing air from the side scoops into the IC shroud may reintroduce that problem.
Or not. Anxious to see how this works out.