If any of you remember this thread:

https://www.rx7club.com/race-car-tech-103/awesome-spin-under-brakes-turn-1-summit-point-683701/

I've got my car under control now. I did a "bad engineering" thing and changed two things at once, but spinning when under the brakes on a straight is a bad, bad thing, so I figured I would attack two likely culprits at once rather than change things one at a time and see if I keep spinning.

Alignment: Was out of whack. I had a ton of front toe OUT, probably more than was healthy. Rear toe was uneven, but both toed in. Now they are even as well. Corner weight was perfect, so I didn't mess with it. Lesson: check alignment often on a car that sees street driving, don't assume it's OK because it was OK last time.

Shocks: One of my rear shocks was dead as a doornail, and the other was getting there, they have been replaced.

Bottom line, the car feels great now and I have lots of confidence when I put the clamps on.