One would think that someone could make a new pipe that perform like the 9886 even with 3 chamber, seems to be a hard nut to crack.
Looking at dyno runs I agree that the 9853 appear the same, but looking at the drawing on them they appear very different.
There are many way to get the same results it appears.
Do you (Neal) know if the P3 .28 as small in the crank case as the P7 Evo2?
I remember gaining a lot from mods in the crank case on those, and even after that it responded very well to larger crank bore.