I'm preparing to do a swap now. I have an '88 4-banger. For the purpose of a swap, that's no different than a '93. I agree, for a swap you're miles ahead if you get a complete car. You can find them cheap, if you're a little patient. I wasn't patient, so I bought a 302 from a wrecker. The motor is out of an '88 LSC. Thats when reality hit me. Dude...you need to get a whole car!
Sooo, just about 3 days later, my sister's boyfriend tells me he knows where there is a whole '88 5.0. I got the whole car for $100 more than I paid for just the engine itself at the wrecker. Sure, the body is crap, but the drivetrain works. I drove it home.
Still, if you don't get the whole car, some parts are compatible.
-The crossmember is the same on my 4-banger as the 5.0, and a lot cleaner.
-You might be able to use your stock tranny ('til it breaks), but the bellhousing is different.
-The underside of the car is probably tapped to accept hangers for the dual exhaust (mine is), BUT you'll likely have a brake line coupler fastened where the right-side muffler hanger should be. This will have to be moved.
-You'll want an 8.8" rear end. Don't even bother with the 2.79 the 'Stang comes with. Go to the wrecker and get a 3.55 or 3.73 from a Turbo Coupe or similar.
...and the list goes on, to be sure. It's more labour intensive than anything else. But get a whole car!