They will fit the gearbox yes. Both IB5's

The 1.4 is a Zetec-SE, just badged as a duratec. The 2.0 is a Newer version of the Zetec-SE in larger form, with no relation to the old "Duratec" in the ST170 at all (which was actually a Zetec).

It will fit straight in as Tim said. But you need to make sure you have ABS as the ST runs its Speedo drive from the wheel ssensors. If you have ABS its plug and play. IF you dont its far more tricky.