Here are some pics of an install I just did in a '97 Malibu. The stock deck was tossed in favor of a new Kenwood eXcelon MASK unit. A Scosche dash kit and harness complete the deck installation.
The stock factory speakers were retained, and the rear 6x9's were replaced with a pair of Panasoic 2-way Coaxials
Phoenix Gold power and signal wires were run to two Patriot amplifiers, each one pushing it's own Kicker Solo-Baric 12" Sub.
The enclosure was made of 3/4" particle board, each sub in it's own .90 cu.ft. chamber.