I recently purchased a Jeep Liberty that already had a (4) 18 4th order bandpass wall. It was 12 cubes sealed and 24 cubes ported. I'm currently ripping the baffle and loading wall out, slowly. I have (16) American Bass XO tens to use from my Astro van flat wall build. I have zero experience in designing a 4th order. Any help with port area, tuning and sealed section size would be greatly appreciated.