Wanna hear something disappointing? My pair of brand new replacement/repro springs have a similar sag to one side. Top of right wheel arch to the ground is about 1/2" higher on one side than the other.

Mine (both front coils and rear springs) are from these guys: http://www.johnrspring.com/
I woulda raised some heck about it, except for the fact that I purchased them real cheep back in 2001 and put them on a shelf, and didn't install them until late 2011/early 2012...LOL. Didn't really have the gonads to call and complain 11 years later when I finally got around to the install. Haven't the foggiest where the receipt is anyway, plus the hassle of having to reinstall one or both again? No thanks...

Instead I got the differential to about 1/4" by relocating battery to right rear corner, and making sure to mount my spare tire to right rear corner, and making sure to stuff my toolbox in the right rear corner, etc...

It's good enough to make me happy...we'll see if time settles 'em further...

They still beat the heck outta my originals...a center leaf on one side was cracked clean in half...making a VERY noticeable sag to one side. I'm overall very happy with the stance and handling I ended up with after replacing all 4 corners and redistributing some weight.

But that is one crowded right side of my trunk LOL!! But that's the best spot for traction weight, so all is good!