Yeah, it's pretty expensive. It's gonna be a pretty penny since I'm pretty sure what you're using is a Chipped P28 with a 28Pin E-PROM chip, right?
If you are running with a modded EPROM chip, make sure you get a 28pin ZIF socket installed. I have one so that I can have 2 separate chips: one for street, and one (not so legal) for track days, and I just change it depending on what I want to use.
You also might want to mod the ECU for datalogging capability.