Here is a list of everything that I came across doing the SPI to Zetec swap
Zetec Engine ($375 from junkyard with 70k on it)
Different alternator ($100 bucks on ebay new)
Different power steering pump ($80 bucks new) and high pressure line ($55 bucks new) to pump
A/C compressor will work if flipped over.
Exhaust manifold and Cat and Flexpipe($35 bucks new on ebay) - I used a OBX header and down pipe ($165 new on ebay), If you do this you will have to have the cheat on the rear o2 sensor. Also if you go with OBX header you will need the coupler for the egr valve pipe where it connects to the header. I got mine at the Ford dealer for $10 bucks.
Auto to Auto Transmission is the same, Torque Converter is the same, FLEXPLATE IS DIFFERENT(junkyard $40 bucks), the Zetec flexplate has nubs for the sensor that the SPI did not have.
Transmission sub harness needs changed to Zetec transmission sub harness for the plug going to the sensor that is not on the SPI
Engine sub harness should come with the motor you get if you get a junkyard motor
Passanger side motor mount ($20 junkyard)
Throttle cable and Cruize control cable ($50 bucks for both at junkyard) - both have different ends to motor.
Main Harness that goes from the engine bay to ECU and Passlock(i think thats what its called) then to shifter and back to fuel tank, needs changed, it goes through the hole that you cant see up under the passanger side kickpanel
Computer and Passlock module Get the keys from the car you get the computer from!
(I spent like $300 for the ECU Pass and harnesses)
Fuel line with regulator ($20 bucks junkyard). It goes from the Zetec intake to the fuel line on back wall. The SPI connections are different.
Air intake tube. I bought the K&N cold air intake($165 new on ebay) made for the focus, it has the MAF sensor mount on it which makes it nice.
Serpantine belt ($20 bucks)
Various cooling system hoses.
I dont know if the Coil is the same because I bought the MSD coil and Massive wires ($135 new on ebay)with Accel silver plugs($40 at Summit). Dont ask why - I just thought it looked cool.
The swap is a piece of cake! Me and a buddy would have had it done in just a couple days if we new all the info mentioned above prior to start.
I did research and found most of it but a few things were left out which caused extra time.
If you are thinking about it. Just do it! Its not that bad at all.
I think I covered everything. Check the timing belt before you put it in just in case it needs changed. Become familiar with all sensors and connections on motor so you know where everything goes before hooking up. I looked at many Focus under the hood and took pictures and videos of engine bays to figure out where all the plugs and connections are. Also I got the Haynes manual - it helped.
I might have missed something but I cant think of anything else now. I have about 2K into the swap.