First off;
The swap is one of two things... your preferrence... and your choice...
The 5.0L swap... you need almost a full donor car... 5.0L H.O.Engine, Wiring Harness, the transmission of your choice, Proper Driveshaft, Pedal assembly if you swap from auto to manual and vice versa... and probably a good choice to swap out the 7.5" rear to the 8.8 trac-loc w/ Axle Dampers. and a suspension upgrade is very recommended.
The 2.3L swap/mod... A 2.3L Turbo motor can be used... but you need a 2.3L Turbo motor, wiring harness,
Tranny of your choice (if you choose to change the type of
tranny), proper driveshaft if you swap the
tranny, Pedal assembly if you swap from auto to manual and vice versa... Suspension upgrade not too necessary but for better handling it is prefferable if you want.
The 2.3L Turbo used in SVO's, GT 350 Turbo's, T-Bird TC's, and even Merkur XR4Ti's, is a direct bolt up to the transmission and motor mounts as the 2.3L N/A motor is built from the same block... but dont think you can just bolt up a turbo... the 2.3L N/A has weak cast internals... the forged internals of the Turbo Block are stronger... as well as the turbo block is also lower compression to deal with boost pressures better.
Remember... either swap is a bit of work but either swap is fun to drive... trust me... I suggest doing either swap... but a Full Swap none the less. Although it is a bit of work... you can do the swap at less cost to you.