This enclosure is so big that it needed its own page! 10.0 cubic feet, or the entire hatch area depending on your view point, is taken up by the subs' enclosure. (4) JL Audio 15W6s call this monster cabinet home.
The enclosure is made from birch plywood and fiberglass. As large as it is, the cabinet is still completely hidden when the package tray is down.
You may also notice the Soundstream 5.25" mids mounted in the package tray. These are used as rear fill and are located there because the 8's are now taking their place on either side of the back seat.
A little excessive? Maybe by some standards, but since Scott competes in USAC competitions, the extra dB SPL helps out immensely. Unlike IASCA events in which sound quality (Sound Q) is the primary focus, USACs scores weigh volume more heavily. IASCA does add one additional point for every decibel over 130 in the Sound Q+ category, but this is still lower than the USAC scoring system. From the looks of this, he should do well in either one!