DD9518I looking for band pass design

[FTL Music]

I have 2 brand DD9518I subwoofers going into a Honda accord wagon. My first though was to build a ported wall but I'm thinking band pass. It will be powered by A soundigital 12k running at 1 ohm. 6 XS3100 batteries and 2 dc alternators 270 amp. I'm trying to it under 15cuft. What do you guys think. I'm not going for spl more street bass.

Thanks

Jerry