96 intake will not work on the 94 engine. I'm not completely sure on this but I don't think the 96 wiring harness will work with the 94 intake. Maybe someone else can help on that issue. Also fuel rail connections could be a problem.
You can't just swap the intakes from 94/95 to 96/97 engine. Here are the links to the information you are looking for. If you have any other questions I think I can help you out as I have done this... and you will have to have to drill and tap some additional holes, close the others but it can be done. I used the intake itself as a guide to do the drilling and longer than normal drill bit. You will also need to use a .409 drill bit to open the end holes since the intake gasket uses them as locating spots.
The electrical issue I can't answer just yet as I'm not quite that far yet. As a far as the fuel rail and the location of the connections some are different, it depends on what car the engines came from and are going into although you can swap that stuff from one to another, not a big deal.
well I just might be parting out the 96 deville if all that must be done. not sure yet. or maybe I might just do the head gasket. I rather not play to much with them.
Thank you all for the info.
If I part out, I will let you all know.