[ZeGermanHam]

Often times a CAI is not particularly beneficial on something like a Vibe/Matrix. Unless you are taking it to redline on a regular basis, you are highly unlikely to feel anything from the seat of your pants. In my opinion, the OEM intake is efficient enough for an economy car, and it's already designed from the factory to pull in cold air.

What you should absolutely NOT do, which I see many people do all the time, is install a snorkel intake with a cone filter that is not shielded and sealed from the hot engine bay air. People often say they installed a "cold air intake", but they actually installed a "hot air intake" that will perform worse.

I installed a fully shielded and sealed aFe CAI on my BMW track car, mostly for bling and the intake sound above 4k RPM. Did I actually feel a difference after installing? Nope.