Just as a heads up, bolt on parts to increase horsepower are OK if they don't add too much power.
Engine designers reduce weight on parts to increase efficiency, so the bottom end of an engine and it's pistons and heads have been lightened to the point of the rated horsepower of that engine.
Raising horsepower 10 or 20% should be OK, should be, but more than that will most likely cause a failure of an existing component.
The 1999 3.0l is rated at 145hp so an increase of 15 to 30hp should be OK, should be.
A 2001 -2007 4.0l is rated at 207hp so might be a better investment, either engine swap or truck swap.
Quick and easy HP increase can be done by using an electric rad fan and switching to a 160deg t-stat.
The electric fan frees up HP that was used to turn the engine fan, not much but not 0, lol.
The 160 t-stat can bring down the engines "normal" operating temp this brings down the intake's temp so brings down the intake air temp, cooler air is denser so more fuel can be added, just as a FYI this also brings down MPG.
This is the point of a Cold Air intake setup, cooler air = more fuel into cylinder.
And that's the point of a turbo or super charger, more air; compressed air can be mixed with more fuel, these often require changing the PCM or chip.