battery amp

Hello I have an amp and subs both pushing 2000watts rms. I want to know if a deepcycle batteey or an agm battery is recomended? Also how many cca?

I'm putting a system in a 95 Monte Carlo and the battery will not maintain charge after running and turning car off. I'm running from the battery to amp then to speakers. My remote wiring is hooked up correctly and still won't maintain charge. Any suggestions?