The Power FC is hugely popular among FD RX-7 owners because it's for the most part the only reliable option out there and the most tuners know what they're doing with it. I know for RX-7 applications at least, it's over $1000. For the most basic Hondata setup which is all that's really needed when having an engine built, tuned, and then left alone (or only tuned by a shop), you can spend a whole lot less than that. Only the full-tilt-boogie loaded up Hondata with all the goodies and such but runs the engine essentially the same will run you similar in price to a Power FC.