4gauge for power and ground will be fine and you can use a 120a or 100a fuse for it. as for the subs use 12gauge
//content.invisioncic.com/y282845/emoticons/2thumbs.gif.fdc3ba010dbb42b61704534b46d02fe4.gif4 gauge wire,100 amp fuse and 12 gauge speaker wire. overkill never hurts though for future upgrades