You can check out the Tasca site for a good amount of parts diagrams for the USDM car:
http://www.tascaparts.com/auto-parts/2014/ford/fiesta/?trim=st&engine=1-6l-l4-gas
Also here are the part #'s for the ECU. Not sure which one is the ST. I could take a look at the markings on mine if that helps you.
EA6Z-12A650-JF Engine Control Module1
E2BZ-12A650-RC Engine Control Module1 Catch Code-CSA2
E2BZ-12A650-TB Engine Control Module1 Catch Code-EWY1
E2BZ-12A650-UB Engine Control Module1 Catch Code-VTE1
E2BZ-12A650-SC Engine Control Module1 Catch Code-YYY2