Yup, I've been doing the math, and my average is about 18-18.5 mpg, about 2 less than what I used to get. I can live with it. But since you're going from 265/70/17, you may not see that much of a decrease in mpg.
From your pics, it looks like you're at stock height. Do you have any rubbing? I do, but it's pretty minor and only at full lock.