1990 da b18b swap should i use obd0 parts or upgrade to obd1

i have a 90 da with ls cable tranny i have the flywheel & clutch and i have the left motor mount bracket and mount and i got a 94 dc automatic that got rear ended with low miles on the b18b

so 1st? is what else do i need to install the the b18b to run obd0?
2nd? how hard would it be to upgrade to obd1? what would i need?

i also have a blown b16a with chipped ecu and the b18a ecu but i dont have the engine any more
also will any parts off the b16a be useful

im not trying to build anything special i just need my car back to a daily driver running properly