i have one box that is about 46 or 47" wide so you would need a big trunk for it. It was designed to fit in a suburban. Its dual slot ported for two 12" speakers. Comes with terminal cups but unfinished.
i will try to get a pic up tomorrow
the other box is built but the speaker wholes are not cut yet so I can make it work for either two 12's or two 10's. This box has a single slot port along the bottom of the box in the middle, tuned to 33hz. It was built a few months ago and been sittin my friends garage untouched so i dont remember the exact dimensions but i think its around 2.5-3.0 cubes.
