With the programmable version there would be no need for the PC. If you got the base, non-programmable version you might be able to use it in addition too, but the PC alone could provide all the same functionality so there would be no need. Pretty much anyway, it does say it can be used with the O2 sensor and I think the PC discards it outright. If you wanted to keep it this may be a better alternative. Also, it's not clear if this replaces the ECU or piggy backs on it like the PC. If it's a piggy back unit I don't think you could run two together.
Scott