I use to have the TRD air filter on my '06 tC, which is the same thing as the K&N but different color, and after having so much trouble cleaning it and oiling, I decided to just buy a Toyota OEM cotton filter. I kid you not, I could definitely feel an increase in performance as soon as I changed it. Good thing I did too, upon further inspection of the TRD filter I noticed holes where light would get through unblocked. Stick with OEM filter, and just change it often if you want to maintain performance.