Wiring was definitely the most intimidating part of the build for me when I was doing the initial research, but it’s really not that difficult once you have it all in front of you. For this build, I’m using a 2002 LS1 harness and LS1 PCM. There’s tons of useful information and guides on this online, so don’t be put off by the electrical work.
Here are some good links:
Since the intake manifold is flipped 180 degrees, the original harness layout will no longer work.