IMO it depends on how much power you will be running, what level you listen at and whether or not you want to be able to run the system for a long time with the engine off. Not meaning in any way to dis what you may have purchased (as I don't know what it is) however based on the amount spent I don't think you have a TON of power going in(?) Unless there is something wrong now with the battery or alternator, my suggestion would be to install your system
properly, upgrade the big three and you may actually find you don't
need either one.
