I have had the K&Ns since I bought the car new. My mileage has remained consitent since after the break-in period. I now have 9950 miles on the car. For highway driving I get 25-27 mpg depending on what my average speed is (between 55- 75 miles per hour). Around town it gets around 20-23 depending on average speed. When driven to work it gets more as more highway miles versus city streets are involved. The above includes having high flow cats and using Royal Purple motor oil.

On my trip down to SC from MD last year I got 28mpg. Traffic was pretty light on that trip so I was able to use cruise control for rather lengthy periods of time. I've never been able to repeat that, car was completely stock at the time.

Not to start any kind of oil war at all, but I would REALLY research that Royal Purple. It apparently breaks down really fast. Just some things i've read.

I'm still curious how people lose MPG when they get an intake set-up... is it because the ECU is making the car run more rich and the car needs to be tuned?

More air with same A/F ratio means more fuel in injectors. The car feels more agile in low RPM (around 1000 rpm). Will wait few hundred kilometers and we'll see.

FYI: Using original 18" wheels and stock tires.

odd as one of K&N's claims is that they get more gas mileage.