Okay guys thanks for all the help so far. Here's my current situation:
I have the Infinity Perfect 12.1 sub running off my Rockford Fosgate 500s amp, Cerwin-Vega front speakers and Audiobahn back speakers (both running off the HU at the moment.)
What I want to do is get a second Infinity, a kicker KX600.4 for the mains, and a Kicker KX800.4 for the subs. My question is, what kind of current will these amps be pulling? The KX600.4 will only be pulling half current at the most, since I will have 4 ohm speakers hooked up to it.
If it's too much, I think I will get a bigger alternator before the amps. Anyone know how to find out what size of alternator I have right now?