Lightning Audio S4.12.VC2

does anyone else have these subs or worked with them before?

curently im running 2 sealed on a Lightning Audio S4.1000.1D its pretty loud in my car right now but i want to go ported and ls2poweredgoat has a 3cu ft box thats being changed to fit 2 12s so im wondering if 1.5cu is good enought for these subs? i know recomended space is 3cu per sub but they overrate that stuff right

if i put polyfill in will it raise the cuft if so how much would i need?