I wonder of SCT makes a tuner for your truck. They should... OBDII started in '96.
Look into a exhaust system and an intake. Get the 180, 160 seems too cold. Also a good pair of headers after the intake and exhaust.
I don't have any experience of the TB mod and have not ever seen proven results so I can't vouch for that. The logic is there though.
Alex, 1998 Ram 1500 SS/T. What the world needs is more geniuses with humility, there are so few of us left.