After several attempts by my wife, a deer, and f_____en UPS to destroy my crazy system plans I've finally made it to the box building phase.

If someone has the time I'd like them to double check my findings here.

I am designing two separated boxes for 2-Planet Audio FU 15-4's run parallel
I have done several box simulations with both Bassbox Pro 6 and WinISD and have come up with a best of 4.3cu.ft(Vb) tuned to 35hz.

Here is the spec. sheet.

I tried running PA's recomended boxes with poor results.(listed on bottom of specs. sheet)