Scotts90 has it right.
Here's what would be best for you to look for:
'86-87 Rangers will have a fuel injection w/ distributor setup and therefore make it easier (but not much) to swap the turbo motor into, since all turbo 2.3L's were distributor'ed stock.
'88 Ranger 2.3's were the first year that Ford put the distributor-less ignition system in these trucks. (I could be wrong, but everywhere I've looked online for the history of these trucks say that '88 was the first year for distributor-less 2.3L's and the last year of the 2.0L, which still was using a carburetor.)
The 2.3L distributor-less ignition motor has a roller cam. This is highly recommended to get, but not necessary.
(Btw, '83-88 2.0L's were all carbureted, as were the '83-85 2.3L's)
'89-94 are all the same mechanically (engine and suspension wise), so that allows you to simply choose which body style you like better. The dash is the same for all of those years too...
Be sure to keep all the parts of your motor to motors built before '94. Motors after that had different journal sizes for the cam and crank. I don't know the full specs on all of that because I haven't had to worry about it since all of my 2.3 stuff is pre-'94.
Scott, did I leave anything out?