You may also want to put a power regulator on it, they are the things that look like tubes with wires comming off them and a little display, it helps from dimming becouse it holds power and when the subs use more than battery this thing will give it the extra boost so that you arnt draining your battery, you can get them for all diffent watages, battery is also one of the best ways to fix this problem

Do the big 3 upgrade. Yellow top optima, H/O altnernator, all 0 gauge power wire. And you dont need anything after that. Make sure to get around 200amp or more alternator.

It doesn't hurt to have a separate battery for your system but not necessary. You're pulling enough power to do it if you want to save the beating your alternator takes evan with a power cap