I'm building a box to fit inside a grand marquis. its going to have 6 12" RE REX12D4's in it. each sub has a .1 Cu.Ft displacement and an Xmax of 12mm (if that even matters). the box is right now 8.02 Cu.Ft. (40w x 26d x 17.5h with it indenting a little towards where the front is) and i need it tuned to 35Hz. Anyone mind helping me out? i have a cardboard port that's 4 inches in diameter that i can cut to any length, but i want it to stay inside the box (if it has to stick out a couple of inches I'm fine with that too).