Racer,

Your amp choices will greatly effect your power consumption. Going with a high efficient Class-D or Class-G/H amp will draw less battery Ah then an old=school Class-AB, while producing the same wattage to your speakers. This means shallower battery cycles and less time to recover. This will mean longer battery life, less load on your alternator, maybe less batteries or smaller batteries. Most all the major players offer full-range hi-efficient amps: (in no particular order) Wet Sounds, Kicker, JL, Alpine, ARC, Rockford Fosgate, Polk, etc. heck, even some price-points like Powerbass and PPi are offering some full-range Class-D.