ZX2 vs. Focus Engine

Is there any physical difference between the 2.0L Zetec engine found in a ZX2 and that found in a ZX3? If not would that mean that many aftermarket parts for the ZX3 are usable on the ZX2?

engine itself is the same (i think) but other stuff is different.....even from year to year on zx2....they changed wires to intake from 99-00

the focus has a different head and no VCT mechanism. they ar generaly concieders different engines for that reason

many part for the focus are not usable on teh zx2

the zx2 engine is better, but ford is stupid so they push the fucus and discontinue the clearly superior car...

the main difference is that fro some reason teh zx2 engine responds very well to an N/A set up but a focus is better responsive to boost