The flywheel is 17lbs.
I spent almost all day fighting with the wiring harness. I realized that there were two ways I could do it: 1) Just blindly follow the FAQ and cut & splice quickly or 2) Make sure every wire was done correctly and that I understood what went where.
I'm glad I took my time because I've learned a ton. I still have some questions, but it's slowly going together.
Here's where I started. On the bottom right is the C101 pig-tail from the donor B34.
This is C103 by the glove box. The engine speed sensor (small black wire) in harness needs to go to pin 1. The White/Black wire from the harness goes to Pin 3. Pin 4 is from the AC switch and goes to pins 40/41 on the ECU (although I'm still verifying this is absolutely correct). To make this all work, I pulled a male C103 connector from my donor B34 harness and 'upgraded' it with a pin in slot 4.
I need to get a B35 O2 sensor plug. I won't need this while I'm running the wideband gauge, but after the rig is tuned, I'll want to go back to stock sensor.
On E32/E34 harnesses the relays are by the ECU, and there's nowhere to mount them securely in the glove box. So I need to re-route those connections to the other end of the harness by the C101. It turns out that the green/violet lines that go to 87 on the fuel pump relay can all be removed from the B35 harness, except the small one that goes through the part above the fuel rail and down to the O2 sensor connector. I re-routed it and spliced it in.
Things should go more quickly now that I've got everything decoded and my confidence in what goes where is up....