I used these supposedly high flow filters many times over many years and I have yet to notice any power improvement and find any comments to that effect highly dubious. I have to agree with ALS, most hear the increased noise and equate that with power. With the paper, no matter how much they pushed the pedal, no noise but with the high flow, push the pedal, more noise and perceived power.
There is only so much air that the engine can use and that is contraol by the mass air flow sensor (MAS) and the gas pedal.
I was in a friends shop this AM (AC Delco repair center) to pick up some parts for a friend. On the counter was this panel air filter that was almost black and as dirty as anything I had ever seen. He saw me looking at it and said, "nice isn't it?" They took that out of a customer car last week, she had nearly 100,000 miles on a older Jimmy and thats was the first time it was ever in for sevice. I suppose the new ac delco made it seem like she had more power. Her only complaint was poor gas mileage.