Next up is wiring the amp power cable from under the hood, through the firewall using an existing rubber grommet right next to the battery (thanks MB) and running a ground cable to a nearby factory ground.
The amp is going under the second row seat, there's a nice little void space with the seat backs folded down. I may try some large velcro patches to secure the amp to the carpet.
The second row seat bottoms are removed, they pulled right off their tabs without tools, very convenient. Tons of space for dual 1.5 cf enclosures in the foot wells, they can be as high as needed to achieve the internal volume.

Once everything but the subs are hooked up and playing, I will mock up the sub boxes using cardboard to get the shape down before cutting plywood. That's right, plywood not mdf.
Also, some people may cringe at what I'm about to use as power and ground cable, but instead of buying new 4ga welding cable like for my last build (runs were very short as amp was next to battery), I am repurposing a set of old jumper cables. They are very thick, probably bigger than 4 ga, solid copper and were free. I see no reason not to do it, especially because I own a newer set of jumper cables already.
Stay tuned for more shenanigans / pics.