Hey wink,
I was looking at changing my gears also. I think I am going with the 3.91 because I drive on the freeway alot. If I were to get the 4.10 with stock tire height, I would be at almost 3000 RPM's at 75-80 MPH. Not so good for fuel economy.

Although if I was to change tire hight and/or rims, this would do something similar to changing out the rear diff.

Food for thought.

 

i'm rarely on the freeway and most of my driving is either city or going 55. If you were to change tire height and rims it would have a similar effect as if you were to change gear ratios... but given the cost of tires and rims it would probably be cheaper and easier to just change gears.