Man, people are confusing today...
If you just want to bolt fuel injection onto your existing engine, then I recommend a 87-91 crown victoria, or mercury marquis ( that is assuming you have a basically stock engine.) Take the wiring harness, upper and lower intake manifolds and the ECU and dizzy. You don't need to do anything about your belt system.
If your engine is has a big cam or replacement heads, then go with a 88-91 mustang setup. This should be a Mass air system with larger injectors.
Either of those systems will fit under the hood without a body lift as long as your body bushings are in decent shape.
If you are swapping engines, my first choice is the explorer, but it still requires converting it back to the 91 mustang EFI cause the exploders have a "locked" ECU and its a lotta work to get it working right.
Tom