#1. Get a performance tranny. (Not some Billy Bob "I do those" rebuilder) But a REAL performance tranny and TC.
#2. Buy a "good" programmer and give it some fuel. These engines can handle a good bit of HP and not blow up. IOW's they were way underrated at the factory.
#3. Buy a good set of gauges and hang them on the A pillar.
#4. Buy a CPS and throw it in the glove box along with a 10MM wrench.
#5. I don't know how good the exhaust was on these trucks but I would buy a good exhaust also.
Boom, you're done.
You have a great truck; and this from an LBZ D-max owner. They don't put out a ton of power but that can be fixed. They can be fixed cheaply and are easy to work on compared to the later model Fords. Best of all, they run forever!
BTW it doesn't take a new truck to run good or to have fun!