yeah i had a box like that in my mustang with 1 DD 9515 and my buddy has 1 with 2 aq hdc3 15s i dont know if it was the box or my amp clipping but i unloaded my subs sometimes....im selling mine depending on what u plan on running in it
This is what I am going to be building soon, kind of a stepped but only 3 inches on each side so not much,just to get over the wheel wells. Its not perfect and dont mind all the numbers just for my reference and to get a visual. Also will be braced with threaded rod just didn't put that in there.
I had one like that with an 18 in my 4 door civic. i had about the same height as you and used the spare tire well to get the other 2.5 or 3" i needed. I really liked it and was probably the loudest ive ever had.