Question 1) They're essentially useless. Waste of money IMO.
Question 2) Highly doubt the "out of the box" chip can be reprogrammed. Put a 350 in it and you're screwed out of a chip.
I say ya just build a mild 355ci. SBC for nitrous use.
Cast crank, forged rods/pistons, AFR 185cc heads, Victor Jr. Manifold and a plate kit...Run a 3.73 gear and 26" ET Street.

Car would move good.