Hi V. My main reason for sealing the airbox is to keep everything inside it as close to ambient temperature as possible. A sealed airbox with cool air entering through airbox intake will run cooler intake temps than a hot box full of hot air. This makes a noticeable difference in summer traffic when pulling away from a stop light. My secondary reason is noise. POD filter makes a lot of noise and it reverberates inside the airbox. Sealed box will make less noise. Matt
