Welcome to TRS
2003 Ranger and 1998 are not too far apart, both 2WD I assume
2003 2.3l was a Duratec DOHC so different that the earlier 2.3l/2.5l 4cyls used in Rangers in 1998
Yes, 2.3l and trans, plus its computer and engine wiring harness, there will be some splicing for 12v and ground that you will need to check on as this was/is not a common swap
Motor mounts, air filter box, radiator and exhaust
Yes, PATS transceiver on steering column, but 1998 Rangers did have PATS as an option so unless the 1998 is a manual trans you may not need to swap out the steering column just add the transceiver and its wiring
The transceiver is not "married" to PATS, its just a powered antenna so can be swapped out without reprogramming
You will need to change the key cylinder to use the 2003 keys, and door lock cylinders if you want them to match
Fuel systems were both 60 psi but fuel line in engine bay will be different, but you should be able to pull the filter to engine fuel line from the 2003 and use it in the 1998 body
You should probably get the 1998 Ranger EVTM like this:
https://www.ebay.ca/itm/142314482199
And the 2003 Ranger "Wiring Diagrams", like this:
https://www.ebay.ca/itm/394934706245
Ford publishes these for every model every year so Ford Shops can trouble shoot new models
They were called EVTMs thru 1998, in 1999 Ford changed the name to "Wiring Diagrams" and dropped vacuum hoses part of manual
They were part of the Shop Manual Set that year but often sold separately
These have every wire for all sub models and engine types that year
And the are basically FREE to use because you can sell them just like the person you would be buying it from is doing when you are done with it
These are always in demand