I've ordered a JVC Navigation DVD player that's going to have SD, iPod, and Aux inputs, Navigation, Back up Camera, HD Radio and Satellite Radio installed. Round 1.
Round 2 will consist of a rhino lined/sealed box with dual 10" Memphis subs getting a healthy 300 watts RMS each...so that should take care of the low end.
For now, he's been painting all the interior parts to match his freshly painted two-toned exterior!!