I need some advice about building a ported or slotted box for my two kicker L7 15's. The manual says for the best deep/spl winning setup it would be 6 cu ft + port; 3.5 X 16.25"port, 13.75" long. What does this mean? how big of a box will i need for both of these speakers? Also should they be sealed off from each other or should they share a port? I have a 4 door blazer and wouldnt mind building a wall, would the system sound good facing forward? Someone please help with some ideas!