I asked my mechanic this question today -
He said - look here:
Got a K&N filter - ripped it apart - unfolded the cotton filter
Took a paper filter - ripped it apart - unfolded the paper filter
The paper filter was more than twice as long as the K&N
More surface area on the paper fitler
He also commented that unless you keep the oil on the the K&N really clean regularly, it can clog up with shit - - the oil just attracts shit and clogs it.
With the paper filter, cause there is more surface area, the shit is spread further (thinner)
Also - paper filters are like 5 bux these days - I could afford to change one every 2000kms - keeping max air flow always.
I think I will stick to paper filters.