I have not noticed any change. The process is easy. The ppe dudes cut out the fan blade looking thing. I cut out one side of it, then popped the rest of it out, because its held in by a couple of clips.
i gained roughly 1mpg doing this and the way i know is right before i did it i sent my PPE standard tuner back to PPE to have it updated to the ET 2 version and while it was stock other then a T/B exhaust i ran 2 tanks of fuel to check my mileage and on the first tank i got 14.6 and on the second tank after i did this CAI mod i got 15.8 mpg so their is a small increase,that was all country and city driving and now with the PPE HOT ET 2 set on 6(350HP)i'm getting 18.7 runnin the same route so it does make a difference and when you put 60k miles on in a years time every little bit helps..that hot et 2 is scary and does it throw the coal..