It really doesn't take a rocket scientist to think through air filtration. Any increase in air flow is at the expense of filtration. Better filtration comes at the cost of air restriction. It is that simple.
The K&N does not filter better than paper media. Under ideal conditions it may filter satisfactorily, and it may not. I have seen diesel engines (more than one) ruined from inadequate maintenance of a K&N, and Ford would not warranty the damage. I have also seen many cases of contaminated MAF sensors from K&N filters that were probably over oiled.
In case you can't guess, my preferrence is paper. However I change it reasonably often. Every 15,000 miles.
