You can get an 02 simulator that will take place of your o2 sensor and make your truck think it still has cats on it. And stick with the 3.42 gears with the 5 speed, you have something like a 4.03 low gear while an auto has something around a 3.07 low gear. And do and eaton posi. and maybe watch ebay for a used programmer. I agree a nelson tune would be better and maybe later when the mods get heavier you can sell your tuner and have Nelson fix you up.