I had the old tires on for a couple of days and I measured the total "lift" or lack of in this case, as it reverted back to normal, that means the springs settle a full 2 inches. Of course, my new lift is *not* Terrafirma.
We had 79 and 80, front and back, before installing the Terrafirma lift, guess what did it measure this time?
Exactly the same, look: