There is a few alternative ways to keep the eec4 ecu.
HKS AIC running 4 addition injectors ontop of the std ones.
Unichip running 4 additional injectors on top of the std ones.
You could also run a 5th injector like we used to on the RST's in the 'olden days'
Problem with both tehse ways is the vast cost and the fact that it is cheaper to go for weber management or even scrap the ford stuff and try omex etc etc which can run any resistance injector etc etc, but unless you are planning a 500bhp monster, probably abit of a waste