The engine is quite big. It was too big for the MK6 (2002 model) Fiesta to fit, that's why Ford shortened the clutch bellhousing of the gearbox.

First make sure it will fit. And keep in mind: it will ONLY fit with a Duratec-HE gearbox, this engine is of Mazda origin, the bellhousing bolt pattern is different. Best choice would be the ST150 IB5+ gearbox. Not sure if the driveshafts will be a direct fit.

It sure is more work involed than just dropping it in like the Zetec. You'd have to weld engine/gearbox mount brackets to the engine bay. Inlet and exhaust manifold might be too big for the MK3 escort so they might need to be modified. And many, many other minor things. The IB5+ gearbox has a hydraulic clutch and cable shift.

I'm quite sure this has been done before. But not as often as the Zetec. You might find some informations somewhere.