Stud pattern should be carried over from previous Fiestas 4x108. Offset im a not too sure, but i would also like to know also, as i have a set of 17inch Focus MP3 rims i wish to put on. Those ford racing ones you linked im sure will fit and an excelent choice. Maybe when you pic yours up this weekend, take a wheel off and it should say the offset on the back of the stokes. Then share for all of us. THANKS.
I will be looking to get one of these as a knob replacement:
http://www.richbrook-styling.co.uk/gear-knobs.
I have the Chrome + Leather one and used in the Fiesta XR4 and WT Fiesta so i can confirm they are a direct fit.