Making custom subwoofer box

I really dislike the R2D2 subwoofer that came with my 2010 Access cab so I want to custom make a subwoofer box and replace the subwoofer with a better one. The only thing is I want to mount it where the old one to save space and make it look more "natural". I am wanting to install an ONX254 subwoofer, I am going to upgrade all the speakers and head unit but I dont wanna go all out with a multi thousand dollar unit. I plan on using 3/4' wood to make the box as well which I have read is the requirement and to leave at least 2 inches between the sub and the wall.

I measured what would be the diameters to mount a subwoofer box to where the last one was and still have the function of my seat belt holder and console in the back. I drew up a sketch of my measurements, I have 1.11 cubic feet of air which is more than needed for this subwoofer. This is my first time building a sub box so any advice or corrections is much appreciated.