I knew the freeway was going to be worse but thought the street would be better. I am getting 22's wheels as well. I might go with the 4.10's. Hard descions

 

You first would need to fully understand a specific engines performance curve along with the load factor(s) and conditions that the vehicle is operated under before you could make a determination as to what effect a change in gear ratio would have on fuel economy.
Generally a higher (numerically) ratio will benefit economy during city driving as it eases the burden of acceleration on the engine.
GM utilizes a specific Hypoid gear cut process that pretty much eliminates any whine noise.

 

I know that, and thats what I need. I want that better gas mileage in city because the wife drives and kills my gas mileage. On the freeway I can just slow down

 

My unscientific observation of lots of posts on several different forums since the 07s came out has been that those with the 4.10 gears have gotten better MPG. How's that for some anecdotal evidence.