A note about the drive shaft: I had heard a lot of options were possible. That I could use an E30 M3 drive shaft or even an E30 318 drive shaft. What I found is that the E36 drive shaft from the donor car had 3 of the four things I needed. So I didn't have to bother trying M3 or 318 drive shafts.
1. It's front mounted to the ZF transmission.
2. It's length worked in the E30
3. It's rear mounted to my differential.
4. It's guibo had to be replaced with one from an E30 drive shaft.
If you look at the picture, you'll notice that the drive shaft is actually two parts. You cannot use half E30 and half E36. The E30 one is opposite the E36 one.

Left is E36. Right is E30. Notice how the E30 one is more robust. Much of the rest of the E30 is like this, too. More robust.

Gauge Cluster Replacement

I had to replace the gauge cluster with one out of a 325i or 325is E30 because the redline on the tachometer was at 6250. The one original to the car was at 4800. I found one off ebay for $50. I've heard if you start with a 318 E30 for your car the redline is the same or close enough but you have to replace a chip inside the cluster because of the difference in the number of cylinders, but I didn't have to deal with this.