What I was saying is that I have seen on dynos where mod motor cars made more power with magnaflows over flowmasters. That is a back to back comparison. Just something I HAVE seen first hand. You guys like them good for you, I love them too. I have single chamber flowmaster race mufflers w/ 2.5" in and 3" outs on mine. And when I want to have some fun pissing off the neighbors, I throw on my 40 series with cutouts.