Rumor has it the Power Factor Pipe does not make a difference on motors under 900cc's. I just installed this exhaust on my Dasa 846SS and Im here to tell you the rumors are FALSE. Holy poop this thing rips not even being tuned. The bottom is the same but the mid to top is crazy. I have stock electronics and a stock pump and the difference was huge. Anyone in the market of this pipe I would highly recommend giving Mark Baxter at Power Factor a call. The pipes are now in stock and they have been extremely helpful during the installation process "my first time installing this system".