I have a 2002 F-150 SuperCrew (4 door). I'm ready to replace the headunit, install a sub, and do something with the door speakers. As for the headunit, I will probably go with an Alpine. I've had one before and I enjoyed it. But does anyone highly recommend any particular brand for headunits? As for the sub, I found an MTX 10" in a custom fitted box that fits under the backseats. I'm not looking for a lot of bass, just enough to give the music some extra "feeling." Now here comes some questions. I've heard of people running power to the door speakers to increase sound quality. Can someone explain this to me in laimen's terms? Where would I put the amp? As for the amp, I'm not sure how many channels I need. If I run power to my door speakers, I'm guessing I'll need more channels. Is this correct? If I run power to my door speakers, how many channels do I need? Or do I need an amp just for those and then one for the sub? Is there a particular brand that someone recommends?