In the big picture the tunnel mods aren't a huge issue vs. the performance and enjoyment of the T56 vs. your other transmission options.
I'm right in the middle of my install, no regretes. Lot's of head scratching, calculating and up and down on the tranny jack but that's part of the fun with the project.
Here's where I'm at in the "challenge."
Engine/trans are sitting at 2.5* with new subframe bushings in this pic.