i have 2 extra, but i havent hooked them up yet cause i hear the more batteries the more strain on the stock alt. ___if you know people who work at a local auto repair store they have some good condition batteries, (anyways in minnesota they do cause people run out and get new batteries when the cold comes around which in some cases its not nessisary (<spelling?)
might wanna get a bigger amp then that, juss for headroom otherwise it looks like you may have to get a yellow top deep cycle battery. It really depends what you are puttin it in like how many acc does it have. You want be powerin them simulaneously but like I said maybe some headroom.
why would you even need an extra battery for that system if you are going to upgrade your alt? like reloaded said, you should get something bigger than that for headroom or if you decide to upgrade your system later to a more powerful one. if 200amp alt is what you are gonna get then get the yellow top and you should be fine.