I have a 72 C20 with a post head unit from custom auto sound, kickpanels with 6.5" pioneers, dual voice coil 4X10 in the dash and 2 internally powered 6.5" Kenwood subwoofers under the seat. The subs are in their own box and the amp is built right in (see link below). I'm very happy with the sound but I was only looking for a good sounding system not mind boggling bass. Without the subs, it sounded like a tin can. This was also the only way I could cram 10 lbs of sh$% in a 5 lb bag. The only real problem I had was good grounds. See "big 3 upgrades" at
www.the12volt.com. This was cure for my electrical nightmare.
http://www.bestbuy.com/site/olspage....=1118845473156