GMFan... I thought you applied POR15 onto the rear subframe. Me, I don't think that would have been either easy.. or that effective, but... Did you have a change of heart?
I found too many rust holes in the frame. See this thread: https://www.bobistheoilguy.com/forums/threads/time-to-dump-or-repair.329390/
rust.jpg
drive.google.com
Mazda Rust - Google Drive
drive.google.com
shock tower - Google Drive
drive.google.com