I do not know if you read through my post of my mods and dyno charts, but if you take some time to read through it and see what happened when I added the parts I did and what it did to my A/F ratio's, it might help answer some of your questions.
I have been looking into the A/F meter kit by Innovate motor sports
http://www.innovatemotorsports.com/
to see if it is something that I want, so I can read my own A/F ratios and adjust them myself using my intune instead of taking it to a dyno shop.
I am not pleased with the last custom tune they did, and shops in my area are not that plentiful, or at least I have not found 1 that know what to do with Chargers.