I did a K&N drop in about two weeks ago. I have used K&N's in the past with good luck. It does provide a little more intake noise and the engine does seem to "breath" better. I have about 9,000 miles on my car and I keep very good MPG records. I have ranged from 28 MPG to 31 MPG with an average of just over 30 MPG. I have s very consistent weekly commute and rarely drive the car on weekends. When I put the K&N in I had 1/2 a tank of gas. At the next fill up I recorded 32.2 MPG which is my highest MPG to date. I need to record a couple full tanks to be sure on any increase. Will post my results after that. So far I am pleased with the change.