I think the same thing. And i didn't see any dyno data in this thread at the moment... oh yeah, one butt dynoplacebo effect.
I remove and re-install both mufflers for inspections each year. I don't remove them for another reason than better sound. I never feel any power increase/decrease for doing it. Only improvement was when i removed cat, once GT18v turbo was installed, maybe it was clogged but i doubt it.
Problem with those snarky comments is people lost their 'appetence' of helping to the others, and that's an issue in forums. My hands are soiled in every car work, don't tell me/us crap please...