NP on the questions....
So, I didn't notice MPG change. I did notice a slight change in suspension feel.
Keep in mind, you have a 2004 - I had 6k miles on my Jeep when I did that. Yours won't be as tall as it has already sagged. In fact, at 40k, mine's not that tall anymore as it has sagged. I'm not sure how much though as I have changed tire size and didn't do the "center of wheel to flare" measurement before lifting.
I'm currently beating myself up debating if I want to drop the $650-$700 for an OME/Rancho setup.