I had to modify a US spec induction kit to fit my Aus spec Focus, including positive crankcase ventilation pipe, brackets, main pipe size,
MAF fitting, etc...
I wouldn't guarantee the US spec throttle body would fit, but the Focus Central one is better than a stock ZX3 one which is still plastic to my knowledge anyway? If Marcus is selling it, I am sure it's fitted to his ZFOCUS and would fit fine.
Tim