I'll echo Stainless' comment about the K&N unit straightening out air. As yrs truly's mentioned on Landracing before, about 2/3rds of the Formula One teams use K&N, plus IRL
Don't forget, K&N became K&N FILTERS because the original owners wanted something better than the oiled/foam stuff of the day. They were motorcylists (Dealers, in fact) that rode California's DESERTS. Ya know, like where El Mirage is.
Thus they have more than one purpose.