Head Unit Vs. amp
I can buy either:
a headunit with 150 amps, eq, and aux. input, subwoofer out $60
2 dirt cheap amps $100
Basically i'm using a headunit as an amp, it wont be used in the system at all, save for a one time stereo eq, then i will leave it alone in my trunk.
My stereo is all stock crappy stuff on a 2002 subaru.
In a carputer a head unit is only going to get in your way. An amplifier is definetly the way to go. You can get a four channel amp and use rear for subwoofers (by bridging) and use the front channels for speakers (parallel wiring). The Ohms will be cut in to a quarter of what the subwoofers are rated at, and the speaker ohms will be cut in half so you wont see any power loss.