Well, let's see.... Fullsac sells a REAL pipe, right Steve? That IS the one that I recommend to folks.
The cat material does NOT impede flow in a 100% stock pipe and performs BETTER than on with Cat material removed. O2s work 'better, I suspect.
A stock head pipe with cat works BETTER than someone we won't name (NOT Fullsac) pipe with NO cat.
This is all data driven by dyno numbers and not someone's simplified way of viewing thing OR adding new cans, which screws up HEADPIPE comparisons.
Most do NOT adhere to any sort of scientific comparisons, and simply go by 'what makes sense..."
End result is this... unless one is poor (yeah right with a CVO bike), the gutting a cat pipe makes that pipe perform WORSE that before one gutted it.
Dave? You really NEED to understand the English language better before you call me out. I talked about STOCK pipes, NOT aftermarket pipes. Crap Dude... you treated me like an idiot.