Box building questions!

[MatthewSladeBrake]

I'm looking at building a new box for my four Kenwood KFC-W3013ps subwoofers.

I'm currently running them in a sealed box to the subwoofer specifications off of a Hifonics HFI2000D.

My question is that I cannot build a ported box to specs for the four subs. I'm planning on a box that is 35"W * 32"D * 13"H. The port on this will be 11.5"H * 6"W * 26"D which gives me a net box volume of 5.38 ft^3, tuning of 32.43 Hz, and port area per foot of 12.83 in^2. So with the subwoofer manufacturer saying I need 2.00 ft^3 per sub even with polyfil I will be below the recommended amount of box volume.

My main question is that since this is the maximum box volume I can obtain in my vehicle, what can I expect from my box in terms of volume? Will I have a high tuning because of the small box volume, or will the "low" tuned port fix this issue?

Any and all advice will be helpful!