these were on my SWB for a couple years, maybe 15k on them. 99% on blacktop around town. twice a year I drive 30 miles of washbarded gravel road. Some very light slow offroad dirt mining roads.
Some specs. and prices can be found at "Rocky Road". That's where I bought them.
out of the vehicle they stand at the same hieght as SR springs , but they are made of thicker wire. I notice I get alot more body roll with the SR springs I have in there now. They made mine sit way to high for a daily driver vehicle, which is almost all I do anymore.
This saltfree dry environment I live in hasn't even effected the gloss on the paint on the springs.
They are supposed to make an SR sit 1.25 higher,,,Montero Sport (which rear wieght is the same as a SWB Gen 1) gets a full 2".
These springs are much firmer than any stock vehicle, better for towing, and give a little more clearance.
They make a heavier constant rate spring for SR but they are designed to have a heavy load on them 'at all times' and I don't think they are any taller.