I need some help with my system...i have 4 jl audio w3 v2 subwoofers dual 4 ohms and i want to build a ported box that will fit in the back of my suv...so far i see that im working with 40-45 inches of rooms from side to side from top to bottom i have 15 inches because of my cargo cover and from front to back i have about 3 feet i would like the port or ports firing to the back of the sub ...regarding the the amplifiers i have a lot of them to choose from but dont know which one will work ,2 crossfires cfa30hc,2 kicker zr360 , rockford 700s...Needing some help here