I picked up a really clean 1985 18XD with a bad lower unit. The housing is cracked (froze) and gears are rusted solid, so no chance of repairing this one. I know the 20 and 25 use the same lower, but what years will interchange?
Pretty much 85 and up will interchange there is a shift rod change later on. Earlier lowers will fit but you need to drill them out for the larger bolts. The later shift rods I believe have a bend in them where yours is straight you may need to swap them out.
