what connector size

hi guys
i need a bit of advice. i have some 5.5mm and 4mm bullet connectors along with some fake deans but which is best for a mamba max with 4s lipos and a 2000kv motor? i can get a hold of some 8mm and 6mm connectors but will they offer better performance ?
should i use 4mm with batteries and 5.5mm with the motor? also are fake deans any good or will they not cope with the current draw?

thanks richard