There's a list in a thread somewhere - I copied the following from it:

Gasket, Intake manifold Isuzu P/N: 8-97237-538-0 list for $18.88 ea (need 2)
Fuel Injector O-Rings 'Gasket; Injector', P/N 8-17113-400 $14.00 bag w/ 16 o-rings

Some other stuff to consider:
Get thermostat and gasket, and serp belt also.
Auto Zone 4060895 / 6PK2275 Goodyear Gatorback). $34.99 + (6PK2288)
Replacing the above while you have everything apart may be a good idea.

St. Charles Isuzu
1-800-727-8066

5 lb pulley (from Alpine - if you want to go ahead and upgrade for more boost)
Older kits are missing the CARB sticker, longer Cruise cable and cruise bracket. Also older kits have the cast nose for the top pulley, instead of the machined aluminum one (I'm not sure if the new kits have this or if it's an upgrade).
Tone can get you the Alpine bits.

The ECU "adapts" so you don't have to do anything specifically to it - some have attempted some tuning but it's not necessary right "out of the gate."

-- John