I have a full-size regular cab '82 chevy pick-up. The truck has 1 original speaker location in the center dash. I would like a simple, low profile, but moderatly high quality system. I have room behind the seat, under the seats, and a center console. A friend suggested 2 tweeters pointing towards the windshield, 2 drivers somewhere, an amp maybee and a sub. I already installed sound matting throughout the cab to decrease the rumble from the engine.
Simply, I want a strong system well ballenced and CLEAR sounding. I like base but I'm not going to, nor would I have the ability to, bungi-cord my trunk and try to set off car alarms. I will need a fair amount of volume output though as the 502 under the hood, and the rubber on the road purrs like a turboprop at highway speeds.
You can fit speakers in the doors with build outs. All you need to do is follow the countour of the door and make a piece of wood that will allow you to mount speakers in there. As for subs I would go with a pair of 10in subwoofers and a decently powerful amplifier behind your seats. You'll also want an amplifier for the door speakers to overcome the engine noise.