The restriction isn't at the airbox, it's at the throttle plate. Your engine can't ingest more air than is provided by the current intake.
Those videos are made by baboons who have no clue what they're doing.
Want more performance? Do all the recommended maintenance, clean your throttle body, replace your plugs, remove excess weight, find lighter wheels / tires, and install driver mods (HPDE track days are a great start).
Here ya go, on the original topic:
https://www.nicoclub.com/archives/kn-vs-oem-filter.html