I read about the false knock and I commented on it in my previous post. However it seems to be hit or miss. The factory cat pipes are thicker and do not amplify engine noises like headers and cat delete pipes do. That is why I mentioned wrapping them.
On a side note, I'm going with Bullets instead of CA. I found the Bullets on Vengeance racing ebay page for a better price. Plus they have the hanger brackets.
http://www.bulletperf.com/chevrolet/...at-delete.html