I have 2 rockford p3 12's and i'm thinking gettin two more and hookin all 4 of them up. These subs are 500 watts RMS each and 1000 peak. I was wondering what my amplifier options would be. Should i try to find one big amp or run multiple amps? Also, would i need to get a bigger altenator or would my stock one have enough power? I drive a 1999 jeep cherokee btw. Thanks in advance. Travis