I have one and love it, so do the people I ride with. No one goes home with bleeding ears. It does provide some power, is a little louder than stock. I think stock is like 90 - 92 db and the eco is 96db. The sound is more of a deep tone rather than loud. I highly recomend this pipe if you want decent power gains (nothing like the ute, but still good), dont want bleeding of the ears, or your riding buddys to make you ride in back.I've never heard of the QS1 before. I am gonna order our
pipes this week. I will have to check into them.