Why would I want added connectors when system already comes with them.?

Answer 1

Well if you mean speaker wire then you want a lower gauge so the signal can travel with less of a loss. And if you mean RCA type cables then a gold plated kind can transfer the signal better again. And a reason for both is for shielding. Maybe I don't completely understand your question though.

Answer 2

The cables that come packaged with systems are not always the best quality. Unfortunately, you can't tell by just looking at them, and they could be quite satisfactory. I would use the cables supplied unless you need much longer runs.