It's very doable, only you can decide if it's worth the effort. You'll need to study the wiring diagrams for both vehicles to see what needs to be changed, what needs to be combined and what needs to be deleted. It won't be as hard as swapping in an LSx motor, but then again the benefits won't be as great either. It helps that you have the whole donor vehicle. Certainly the Vortec would be a nice upgrade from the TBI.
Mechanically, it should be a pretty simple swap. Cooler lines will bolt up, but will need to be flushed. The '97 ECM will go where your windshield washer reservoir is now, so you'll need parts like that from the '97 as well. I'm pretty sure your current ABS does not talk to the ECM--it doesn't on my '92--so that will be no worries. Don't forget the exhaust off the 97 as I don't think your y-pipe will bolt up to the vortec.
What you want to do--what I would do anyways--is trim both harness's back to what they'll control. your 93 harness will lose any engine connections but retain functions that the 97 won't be controlling. (AC, headlights, 4WD connections, etc.) The '97 harness will control the engine and trans. This is time consuming work that must be done right the first time. Some of the circuits from the 93 harness will be needed to power the 97 harness. Carefully trace each circuit on the wiring diagram so that you know what it does and what to do with it. Save all of your old circuits that are hot in run, start or battery--you'll need them to power the new harness. Don't cut any wires too short till you're positive you won't need them anymore. Verify that your old ECM won't be needed anymore. Mine controls nothing but the engine, but it's possible yours controls more than that. I don't think so, but verify that by studying the wiring diagrams for your vehicle. How is your fuel pump, your AC, etc controlled. How will they be controlled after the swap? You'll have to determine these things.
In a lot of ways it may be easier to swap in a LSx motor, as there are harnesses available for a reasonable price. Still, you could do the 97 cheaper because of your access to it for a cheap price. So it depends on how valuable your time is and how much you can spend. Swaps can get very expensive very fast. The 97 swap is nice because you have all of the parts available right there on the donor vehicle so you won't get nickel and dimed to death as bad as another swap. Then again, you're going to a lot of effort to swap in a nearly 20 year old engine and trans. You might be having to rebuild stuff again pretty soon. Given the effort involved in the swap, I'd rebuild the motor and trans before you swapped them in.
No matter how well you plan it, there is going to be a lot more to do than you realize in any swap.
