1. Decreases the temperature of air entering the engine and hence produces more power with the same amount of air.
2. Increases 10 to 20 horsepower depending on the make and model of your vehicle.
3. A cold air intake can actually increase your fuel economy as your engine "learns" to work more efficiently, thus needing less fuel to     run. Thus, you're getting more horsepower with the same or better fuel economy.
4. Low resistance to air intake, better acceleration.
5. Better filtration.
6. Increase BHP.
7. Available in different sizes (3"-8" Mouth size).
8. Enhances the look of your vehicle's engine bay.
9. Produces an awesome sounding "throaty" intake sound.