My dad god rest his soul taught me alot , one thing he lived by is Believe none of what you here and only half of what you see. So proof is only what you experience yourself. and without that you will never know for sure.
If this is true can you explain how members here have noticed power increases when switching? I question this because I see this a lot since it didnt work for you it isnt possible that it works for someone else. Maybe this article would help proven dyno results. http://www.carcraft.com/techarticles/exhaust_system_installation/index.html
