which one?

I have a fosgate power t1 12", Im borrowing a friends box until i build mine.  rockford fosgate recommends this sub to be in a vented box with 1.25 cubic feet of air space. I dont think that is big enough so im gonna put it in a 1.75 cu ported or vented. I wanna build a custom box with 2 3" ports. but i dont know if i should just build it vented or go with my idea. the box its in is like 2.25 cu and its way too big. all the sub will hit is really low bass. rock music dosent hit on it at all and i think its cuz of that big ass box. it might have something to do with my vehicle tho...its a extended cab chevy and i dont know but it only hits the lows. but back to the subject...which would u guys go with? ported or vented?

That sub will sound great in the 1.5 cubic feet vented enclosure,you will have to drive this sub hard to get a great sound in an extended cab, I would recomend putting a spacer in front of the sub about 3" and face the sub toward the back, This will sound better and get rid of any noise you might get through the port. ( tuen it to 32htz)