LMAO.
That gauze is about the coarsest fibred material you can get. Its flow restriction will be nil. I mean ZERO. Its there to prevent larger debris clogging up in between the paper vanes on the main filter element. - Granted, if the filter is years old and the gauze is completely clogged with dirt then it will cause a restriction, but without the gauze, that dirt just coats the paper element anyway, so there will be no actual change in air flow.
Anyone claiming that a car goes noticeably better between a standard new filter and a new filter with the gauze removed is talking out of their hoop.