FAQ about the 3 liter can be found
here. As far as you getting a used or new engine in Europe, we're not quite sure what you have over there in salvage yards. The known vehicles with this engine are Taurus/Sable, Escape, Licoln LS, Jaguar S-type and a few others. The Lincoln and Jag will take the most work to swap since they have different heads and water passages from the factory.
The closest match for a swap is the '98-'99 3 liter from a Taurus. With only a few block mods needed, you can maintain all of your factory sensors. The knock sensor included. Only the newer 2000+ 3 liters need the knock sensor hole drilled and tapped for a '99 or older Contour. The 2000+ knock sensor will match the 2000+ Contour knock sensor if you didn't know.
