Sundown SA 15 box help

[Reed Farrar]

I just ordered two sundown audio SA 15 d4 subs. I have a CT sounds 2500.1 that i plan on powering them with. I have a 2001 Oldsmobile alero 4 door, I took out my back seats and plan on puting a box back there since theres no room in the trunk. The amps are going in the trunk along with the battery. I have been doing research trying to find some box designs online but could only find 2 box designs that are slightly to big to fit. So if anybody could help me with a box design i would appreciate it alot. My max dimensions for my back seat are 26 height, 21 depth, 34 width . recommendations are 3-4 cubes 35hz. i would like the box to be on the smaller side but not to small maybe like 3.5 cubes to each sub or 3.2.