I think that cables, be they interconnects or speaker, make a difference. Ive test listened to equipment that sounded different when the cable was changed.

A little theroy to bore you all. In every cable that runs next to another cable or over another cable there is a capacitive charge and an inductive charge. These create noise and signal loss. One of the easiest ways to limit the noise is to have a cable that is twisted. This is much easier done at a wire factory than at home!

The reason a larger wire is better is to limit the amount of voltage drop going to the device. It also allows a higher current rating for the wire. A larger wire disapates heat better. This is more a concern in electrical supply concerns. Hope this helps out a bit.