I may throw the factory lid back on next trip along with a new dry flow reusable filter, which won't be for a long time. It will interesting to see if the shorty headers and 2.5" X pipe exhaust and 1.5" taller tires actually help mileage. I actually put back on the steel rims with skinnier 205/75R14's on the front 215/75R14's on the back. It should drop RPM's to 1750 at 60 MPH, so 70 MPH will be around the same as what 60 MPH was. We will see.