If you have seen many many studies that show K&N filters let a meaningful amount of dust through, the studies are either flawed or they don't know what meaningful means.
I have a total of almost 500K miles on two different Rangers with K&N fair filters on them and there was absolutely no sign the filters let a meaningful amount of dust through. I had the oil analyzed on my 89 STX each oil change and there was no indication of dust getting into the engine. With almost 200K miles on it when I sold it to a co-worker, it used no more oil than it did when I bought it new. My current 02 FX4 is approaching 300K miles and it too uses no more oil than it did when I bought it new. So, if K&N filters pass dust, it certainly is not meaningful or the rings would be worn and those engines would use more oil.
I typically spend 4 weeks every year off-road in dusty conditions. I travel with groups and usually eat a lot of dust that is kicked up. When I clean the filter after the trips, it is caked up heavily with dust on the front side. The back side is as clean as the last time I cleaned it with that pinkish color still showing. I also wipe the inside of the intake tube with a white cloth and there has not been any sign of dust.
If you want to trust those studies, that is up to you. I prefer to trust the 500K miles of experience I have with K&N air filters. I am not trying to sell you on them, I just don't like bad advice being advertised. Of course, K&N air filters must be cleaned and oiled properly for them to work right.