Yea not bad numbers at all considering he had the delete plates on the before run. If he had the stockers that could bring the total gain to around 10+ peak hp. I'm wondering this too. It looks to hover around 13.5-14 right to 4500. I know when I did my dynoing my car started to lose power with my afr above or below 12.5.Not bad results for what the manifold was designed to do (rev to 7k+). I wonder if it would pick up a tad of what it lost down low if the AFR was brought back inline with what your before dyno showed. Do you know if there is any data on this manifold showing the flow differences between intake runners? As long as this manifold flows more evenly than the stocker I don't see how I could go wrong with adding this manifold to my setup.