Chads02Z28

Ok, Saturday I just bought a 98 C5. It has a Eclispe indash DVD player with the brain in the trunk, a Alpine V12 5 channel amp, going to Boston Acoustic mids/highs, and a 8 inch sub. I have a good amount of stereo knowledge, but I thought id ask before i dove into it. The 2 speakers by my head/passengers head, is working fine, clean and loud. Sub works fine. Passenger door very quit, and nothing out of the drivers door. Ive tried fading and balancing and nothing. I havent gotten into checking ohm loads or anything yet, but all wires are connected, Anybody have any tips about the Eclispe indash dvd player? The Fade and balance is self explanitory, but then theres the FR/FL and Rear, I know where they are talking about, but whats that do? Also what size and how hard are the door speakers to get too? I know i can probably figure it out, just wondering if anybody had some good tips before i dove into it.