VSII-style is the only one I have seen that seems any good.
VSII-style carbon fiber hood for 2009-2010 Nissan 370Z
In general this is the airflow for all cars. The front of the hood is low pressure, as you get to the rear the pressure increases because of the windshield. A vent far enough towards the back of the hood would slow airflow in the engine bay, it's also where most cars have their air intake for the cabin because air is being pushed down and into the vent system.
