Some popular brands are AEM, Injen, Comptech. A short ram will generally give you more low end power, less high end, while a CAI will do just the opposite. The AEM V2 claims to have the best of both worlds, but are really nothing special. If buying an ebay intake, we recommend you get a k&n cone filter for sound quality and filter durability.

Here's the difference between CAI and SRI's.

Cold Air Intake (CAI)
PROS: Since its farther away from the engine it get colder air wich carries more oxygen thus creating bigger explosions in the engine thus giving more horse power.
CONS: Since its a longer pipe it takes longer for the air to get to the engine (less throttle response), since its closer to the ground there is a risk of getting water into the engine causing it to stop.
Neutral: Poorly designed CAIs can gain little, no, or even lose power.

**The cold air intake may have risks but they can be avoided by intaling a bypass valve which is designed to take in large volumes of air with a sudden thrust of the gas pedal and will safely level off and switch to your primary air filter as you coast on the highway. **

Short Ram Intake (SRI)
PROS: Smaller pipe so air response is faster, almost no chance of water getting into engine.
CONS: Since it is closer to the engine it heats up when the car is at a stop and delivers hot air with less oxygen molecules causing the HP to go down.
Neutral: Louder, deeper sound- pro to some, con to others

** Temperature difference is gone when the car is in motion, there is enough air flow to forceably scavange hot air out of the engine bay to be replaced by colder air. **
**However, SRIs with a well designed heat shield can lessen the issue of hot air.**

Note: At any rate, a "good" CAI vs a "good" SRI are practically equivalent when at speed.

Bottom Line:/Any intake is better than a stock intake because the internals of the after market intake is smoother and tested to perform better than stock. stock intake air boxes allow LESS air than moded intakes. MORE air = MORE power!