RAM Air systems, like this one ..
Looks like it relies on air being forced into the intake by forward motion. If you haven't already noticed, the intake is right near where the bonnect shuts - So when it's closed, even when you'r driving air doesn't get FORCED into it ..
So i think these systems are somewhat pointless .. Similar to those SS Induction ones.
In Gaurd CAI with Silicone Intake is pretty good mod and you can do it fairly cheaply.