You think the change from 4.06 to 3.84 is going to net you any discernable gas mileage improvement?
Anything within a couple hundred rpm is going to net about the same mileage return on the highway.
If you want to get technical you will need to apply more gas pedal in city driving to attain the same power needed to accelerate.
Either one will be miniscule changes up or down in the grand scheme of things.
