Box request for infinite913 want to wall my jimmy at the C-pillar!

I have a 96 jimmy that I want to add another 18 to but I have to keep the backseats. I am able to wall at the C-pillar and have the port blow in. I will be using 2 18" zcons from SSA they are rated at 2500rms. Right now I got the one sitting in a 7 cubic encloser tuned to 33Hz. I am currently using the SAZ3k. for the new setup I will be using the Stetsom 5k2d at 2 ohms. It pushes about 6800rms at 2 ohms at 13.8 volts. I would want the new enclosure to be tuned at 33hz because it will be used as my daily vehicle. I will be have 2 xs d3100 in the back so we will need to take into consideration that! Thanks for all your input ahead of time!

Width above wheels is 59 1/2"
Depth from top of seat to back is 38"
Depth from bottom of seat to back is slightly under 40"
Height total is 59 1/2" with ceiling out!
width of wheel well is 40"
Height of wheel well is 7" not sure on length