Working for Nissan, I've learned that the GT-R's fender vents are opened for one purpose: lower drag. By allowing the air to escape the fenderwell, the pressures are lowered and witchcraft happens, allowing teh car to slip through the air more efficiently. They're not tied in with the engine bay at all.

Regarding the heat aspect -- if we could somehow tastefully incorporate NACA ducts into the hood, and line these up with a perforated tube linked to the side vents, it would provide a low-pressure slipstream to assist drawing the hot air out.

Now if we could only get the hot air out of this thread...

Ram-air or not, there are definite advantages to facing the air inlet as directly forward as possible, as unimpeded as possible. Otherwise, you wouldn't see F-1 teams place a saucer-sized inlet above the driver's helmet. Skeptics of ram-air abound, but the air ingested into an engine with a forward-facing scoop is always going to be at a greater volume/pressure than a rearward-facing scoop.

F-1 teams have millions of dollars, countless hours, and endless resources to play with. We don't. They build cars based on what works; anything more detracts from performance, anything less undermines it.

Brake ducts, air inlets, radiator cooling surfaces -- all face forward.

The only thing opened towards the rear is the underbody diffuser, and that's to scavenge (remove) air from underneath the vehicle as quickly as possible.

Which, brings me back to my GT-R point.