I used the AEM 30-1300 it cost $1,300 on e-bay, they aren't available any more, unless you know a Mitsu Tuner shop that has one still ion the back shelf.
i used to have an Apexi AFC II that is started with before the turbo to piggyback the Stock ECU to have some fuel management, but once i went turbo, it wasn't enough, and yes, I sold the Apexi unit.