To be honest, I haven't run across anybody that has done it to an 800, only 700's. Gutting removed the weight and they did run well. It's like anything else you do. Typically 3 or 4 mods are needed to make a total performance package. In the cases I know of; Air Horn, Can, Reeds, and clutching were also involved at the same time. With that being said, all things done, the sleds ripped.
You save a $100 by doing the Bikeman Pipe Mod. You also pay shipping ($30-$40). Now is it worth it to save $60-$70?
IMO: Buy and Slp pipe. Reasoning, you can sell your old pipe to someone mid season that has hit a tree. Or maybe it will be you. Or you have the option to put it back to stock when you sell it. I totaled a Rev last season and pulled my PSI pipe off and put the stocker back on (sold it for $200).
*****snow*****