For anyone looking for a solid 5 channel and don't want to spend an arm and a leg this is the amplifier for you:
http://www.amazon.com/MB-Quart-ONX80-4-500-Performance/dp/tech-data/B00375LC6Q/ref=de_a_smtdDoes 80x4 @ 4 ohms and outputs 500wrms off the 5th channel so you can run all your door speakers and 1 subwoofer up to an Alpine Type R or CVR equivalent. (500rms obv) these do rated with clean power and good efficiency for $300 brand new you really can't beat it.
I'm posting this due to the amount of people wanting 5 channels, well look no further!

the monoblock side supports 1/2/4 ohms and of course 4 channel side for 80x4 @ 4 ohms. I'm thinking about picking one of these up for the hell of it you can get it a bit cheaper from:
http://www.onlinecarstereo.com/CarAudio/p_25335_MB_Quart_ONX480500.aspxBut I prefer Amazon, your choice though.
This post was edited by Hellish Orc on Mar 26 2012 11:40am