How to find the OBDii port on your Focus mk3 including ST / RS
It sounds simple right? But Ford hid the OBDii / OBD2 port on your Ford Focus mk3 pretty well.
It's tucked away behind your coin holder type pop out storage as this video shows.
Once have had your Focus ST or RS (or indeed Ecoboost or diesel) remapped, then consider adding a Steeda OBD Port blocker to stop unknowing Ford techs over-writing your remap with a factory ECU update: