If you search the site you will find a bunch of setups.

I have a single 12 under the helm but mine is in a sealed box I built. I used the front panel as the face and added the box to it. I lost no feet room but was a bear to get in.
There are custom installs with ported boxes in the same location but you give up most to all feet room. The "infinite air" subs do not sound good if you want punchy bass like your truck.