I ordered these from Hauck and thought they were the CPR pipes like on my last 02 Viper I had and there Aaen pipes. They swear that I will get the same results. They also say they fit better and are quiter. We will see. Titus talked me out of sending them back. They better work. I found a dyno online of a few different pipes on line, and the slp pipes had 146hp at 8800 rpms, speedwerx had 142hp at 8700 rpms bender was at 144 at 8700 rpms and Aaen was at 140hp at 9200 rpms. I don't know how accurate this is but time will tell.