Wow,...that system is awesome!
Mine is nothing like that, but it packs plenty of punch and is almost invisible to the total operation of the car.
I installed a sony Xpod head unit (it is rather dated now, but works fine so it stays put). I have infinity speakers in the lower kick panels, and installed in the rear custom deck box.
I have a RF 500 amp under the passenger seat.
We built a custom box that just slides in the rear deck and allows the convertible top to clear by a whisker. It houses two 10" subs with isolated mids to each corner.
The infinity speakers run off the head unit power, while the twin subs run off the amp alone.
It will never win a competition, but it does get your attention, and you can actually hear the stereo and feel the base when cruising down the highway with the top down and big block roaring through the spiral baffles in the sidepipes.
Oh, the box is made of MDO (?) wood, glued and screwed together with biscuit joints. I then ground it down and wrapped it in two layers of fiberglass (medium mat). I ground that down smooth and then sprayed a full layer of epoxy truck bed liner on the fiberglass shell. This allows it to blend into my black interior, resist moisture (a real issue with a convertible car that actually gets used rain or shine), and trap the sound waves in a bit longer before allowing the boom boom to happen.