ok so lets do a little math....
according to kicker the sub will take up 105 in3 of space.
at 1.3 cubic feet = 2246.4in3
total box volume needs to be 2351.4
so lets just say 2350in3 to make it easier.
you have a 12 inch sub so you will want the face to be atleast 12.5 by 12.5 on the inside. (those two can be smaller if you need the box smaller to fit in a specific spot in your car, the sub should face the back, so be sure to measure the car first so that you dont build the box only to find that it wont fit) So that gives us one set of dimensions.
Now 2350 = 156.25 * (inches deep)
(inches deep)= 2350/156.25 = 15.04" deep.
so that is one possibility for the interior volume 12.5 * 12.5 * 15
make it 12.5 high and 14 wide = 175
2350/175= 13.43" deep
so now that you see the jist of figuring out the volume you need to plan out what pieces overlap and what ones dont.