I cleaned my stillen air flo on the weekend and it made a huge difference(not like a supercharger or anything but a definite improvement
While it's no surprise that a clean filter performs better than a dirty filter
What is surprising is that how dirty mine had become in a relatively short time.
According to the K&N filter recharger kit you're supposed clean the filter every 50 000-100 000 miles on street driven applications and more often on off road or dusty conditions(which I didn't think I had been doing)

I cleaned mine at around 23K which I thought was early and I'm now going to be cleaning it around every 12K.
How frequently does everyone clean their air filter?

 

i have two that i alternate between but it ends up getting cleaned around every 12k-15k. with an open cone it gets alot dirtier than a panel filter inside of an airbox.