Buy 2 gauges of the same wire and same connectors (or bare) and have fun answering your own question. I did…bought Kimber Kable 8TC and 12TC. On my system I could hear a definite all around improvement in the larger gauge 12TC. Fuller sound, improved bass, deeper stage, highs not so much improved which was good thing. Since moved on….higher quality wire such as silver plated OCC copper, better construction geometry, connectors made more of an impact than wire gauge size for me.