might want to consider a big 3 before anything.. appx 10-12' of 0/1 gauge for that plus another 20-25' of 0/1 from the front batt to the back. If you have at least a 120A alternator and a solid (at least) yellow top under the hood with the big 3, then you 'could' get by without that extra battery.. good rca's, 8-12 gauge speaker wire, accessories..