Dont some of the EVO models have rear facing vents?
But vents in most applications vents are a joke and make automotive engineers laugh when goons with no idea put them in. Even many factory vents serve not purpose. In some cases exit vents in the bonnet will reduce airflow around critical areas such as the oil filter, sump, front diff and oil cooler. Raising the rear of the bonnet is just as bad the air will flow through the radiator then up across the top of the engine and out the back. It will not flow over the exhaust manifolds, turbo, oil cooler, sump, diff and gear box.