Looking for some help in direction, ported versus sealed, keeping usable space and any other helpful info.

I am running a Kaption 15 and their 1000 watt amp.

Your thoughts or suggestions?

I am taking the 3rd row of seating out...

 

Big enough box, 4-6 cu.ft. tuned to 30 hz, unless you up the power then you should be good with a really big box.

 

Here are the specs:

http://www.kaptionaudio.com/manuals/SPLManual.pdf ( I have the 15 inch)

http://www.kaptionaudio.com/manuals/KaptionD-Class.pdf (biggest amp they make)

I just want to make sure I do this right the first time. I will be going to an Fi later, but this will have to work for now.