Help

[dazzlerr6]

As a newbie to doing things this way I've just finished put my electrics in car and want to no how n what size connectors to put on the wires for the connecting between esc n batteries or does it go buy what batteries you buy I want to run speed power 6500 which I've seen some one else run in a cat sx by the way the esc is sp gt2 pro if that makes a diff any help would be great many thanks