So on the advice of my trusted, independant mech, I had him "fix" my catalytic converter.
All I can say is HOLY CRAP!!!! Turbo response is instantaneous; there is absolutely no more lag whatsoever. I've put a tank of fuel through it and, so far, my mileage is sitting at 14.9MPG.
There are a couple more things I want to do. It's my understanding that you lose 1MPG for every 400lbs you're carrying; I have a hauler bed that weighs in at 1400lbs and the Ranch Hand bumper weighs around 400-500lbs. I'd like to go back to the regular dually bed and front bumper...that should shave off at least 1000lbs I would think.
I might just yet take out the last line of my sig!