A short while back I posted a statement to the effect that my use of K&N filters boosted mileage and performance in my two new Honda cars (civic hybrid and Element both 05). After putting about 5000 miles on the Element's filter, I took it out for an inspection. It was filthy!!! This I imagine is what an air filter is supposed to do. As for those of you who so kindly responded to my original post of the same topic, I'd like to thank you. You've more than ever convinced my of the efficacy of this filter system.and its claims for increasing mileage and performance. By the way, my Hybrid is now getting over 49mpg in mixed city/highway driving. I imagine it will improve even more on long highway trips. Again thanks all for your contributions.