I'm trying to decide what box i should run in my 2011 Nissan Altima coupe box wise..I have a kicker L7 10" and a Kicker SX 1250.1 amp, i think i need a ported box but not totally sure, i'm guessing around 35 to 40 hertz? and around 1.5 cu ft? Does anyone make a prefab box that would work good for my set up? I need to stay at 13" on the height. Also, how do you figure out hertz? I don't mind building a box and realize it may be my only choice but i would like to see what some of you guys would recommend and maybe get me going in the right direction.