There are a few aluminum panels that need to be riveted in place. I think there were 5 panels. The newer kits only have 4, I understand. I added some beads to the panels to make them look better, and to prevent oil canning. I bought a cheap bead roller from HF about 12 years ago.
I painted the firewall side with ceramic heat barrier paint. Probably won’t matter, but there’s that OCD thing again.
If you don’t have a set of Clecko’s, get some. They’re very handy and will save you oodles of time and effort. Breeze Automotive is a good source for these. Get mostly 1/8″, but a few 3/16″ are pretty handy, too.
The transmission tunnel is pretty simple. Don’t expect to get it to seal, because that’s not going to happen easily. I drilled and tapped holes for #10 screws. Smple, effective, and cheap. Some people like to use Rivenuts here, but I don’t see the point.