I recently installed the AFE proguard7 filter. I am impressed. Noticed better acceleration right off the bat, from my stock box. Now after putting about 1,000 miles on her I have also noticed better fuel mileage. I was averaging 16. 6 mph, which is a combination of around town and highway miles, Now am getting 17. 2 pretty good mileage for a 1 ton with 3 tool boxes and 800 lbs. of tools.