Installed my new waterproof immobilizer case.
Not quite as easy as I thought it would be - the two harnesses still looked factory new, right down to the cloth tape wrapping them. I had to rip sections of the tape off in order to get the silicone sealer down in between the wires. The harnesses also fought me tooth and nail when I tried to mount the board into the new box - the board has to sit over two indexing pins and OMG, the harnesses kept making the board pop up, but I finally got it down and the cover on.
A really nice, well designed, and well put-together kit. If you follow the instructions (or the YouTube video) anyone can install it.
The whole process took about an hour and a half, including seat removal, vacuuming the area under the seat (I found a quarter!) to remove 17 years of dirt, etc.
I just need to clip the (super long) zip-tie and reinstall the seat (I'll do that tomorrow). Oh, and I'll probably need to clear the airbag light since I powered up the car with the drivers seat out to make sure everything still worked.