Anything over 2 k in amp power you upgrade your alt to a bigger one at least a 200 amp or larger and one extra big agm battery the xfl subs are the American bass subs What everyone is missing in your thread is that you want a navi deck and everything else with your budget. Most if the suggestion given would only be subs .box, and amp that would use up almost your whole budget It will be plenty loud but that really depends on the install. But you won't be disappointed with this set up at all. Has everything you want in your budget as well and new with full warranties Used is fine. But it's still use no gaurantee on the equipment if your amp or deck messes up in say 3 months your buying another instead of having it fixed or replaced under warranty