The system comes with an umbilical cord that connects the sub and the amp/source. You can use whatever wires you want from the speakers (which go into the sub) but the umbilical cord is a one off and not duplicated by anyone else.
It does say in the instructions that you can wire straight into the source from the speakers and I meant to experiment with that but haven't bothered as yet. I'm not sure what the point is of using better cables for the speakers if you are using the umbilical, as surely that would be the weakest link
Best wait for someone more 'techy' than I to give you a more concise answer.