You don't need 0ga, 4ga for the amount of power your are running is perfect. TURN YOUR BASS LEVEL DOWN!!! Your clipping the s
hit out of that amp and going to blow your subs. Set everything to zero, get a DMM and set everything correctly. The yellowtop is fine, I still don't think with the amount of power your running you don't need a bigger alt. Just get a 2nd small AGM battery, not a full size one
Ebay Link, the optima up front and the big 3 with either 0ga or 4ga. My GTO has 4ga for big 3
Never had an issue with optima, really don't think he needs bigger alt with 2 batteries and that little of power.