Ok here is what I think you should do, get that alt, get an xs s3400 for up front, it's a good starter battery. Then get at least one xs d3100 out back. You want to do 2 runs of 0 gauge to the back battery. Make sure you have a fuse in line to the back battery. That should be more than enough for that amount of power although that alternator probably doesn't put out enough amperage to keep those batts charged if you run the system at full tilt for a long period of time. What amp are u going to be using