I installed the filter, which the air box was secured like Fort Knox (torx screw heads, one under the air hose so you had to remove that, and then two locking cam slots - really???)
I must admit I cannot hear anything different yet, but my ears are plugged from a head cold in China and the airplane ride home locked them in. I will post after my head clears, I also plan to do some 5 to 70 MPH runs with both filters to see if there is any difference.
Did anyone install the white "bug screen filter mesh" in front of the K&N filter?