RDF1

Ive always been happy with Circle D for converters.
Depends on your cam but going with a 3000-3200 would wake it up substantially.

I agree with Dan the man also. Dont go get cheap injectors without data. Ive used Fuel Injector Connection for years and the guys there have always been good. They have all the data for each injector so its a easy swap.

Just dont go with a cam thats too big or a converter thats too tight. I get wayy too many of those to work on and they are miserable. but they just wanted it to sound cool at idle..

tjmath

100% ditch the shorties and get a set of long tubes. You didn't mention, or I didn't see, what the rest of the exhaust system was but I would recommend a good high flowing muffler like Magnaflow or something straight through. Definitely give Circle D a call and they can spec you out a converter for what you wanna do with the truck. And you definitely want to get it custom tuned to take any benefit from all the mods.

Don't expect that built 60e to last very long. Notoriously the weak link in these truck for a long time.

Fast355

Stage 3 only really builds more power over the Stage 2 above 5,500 rpm and actually loses some low-speed torque. Too many shifts close to 6,000 or over will help hasten the 4L60Es demise.