My last two cents … when I bought my ‘66 Formula S, it had rear end sag. My assumption was the springs were worn and aged letting gravity taking its effect for 50+ years.
I ordered my Espo springs as stock, not the +1 or +2. The replacement changed my car, giving it a slightly raked look. (They were replaced about four years ago, have not “settled” lower.) It gets compliments. Expect replacements of any kind to do this to yours, unless you go with a de-arched (lowering) spring.