That link doesn't work and I'm only vaguely familiar with the turbo kit your talking about.

The ERL MF2 allows you to run additional fuel injectors like its name implies. You have your four stock injectors in the manifold which are controlled by the stock ECU. Now let's say you add a couple more injectors tapped into the charge pipe. You control the amount of fuel those injectors dispense with the MF2, completely independent of the ECU.

Fmax uses a setup like that in their kits, the charge pipe is tapped to accept two injectors and with the kit you get the injectors plus a preprogrammed MF2.