I finished replacing my front shocks and springs at 120,000 miles. First, thanks to all who helped straighten me out on which shocks and springs I needed. I did this because I could feel a sort of rebound in the front end when going over a sharp bump. Kind of like this blue Bump Before shock replacement line on the plot. I felt the same thing in our old Pathfinder at 150,000 miles and replacing the shocks eliminated the rebound. The front end feels much better now, more like the red Bump After shock replacement line.
I think there was definitely something wrong with one of the shocks, probably the right one. When I disassembled the struts they came apart internally. The left one gushed about 6-8 oz of black iron oil making a big mess. The right one only leaked 2-3 oz of foamy yellow oil. You would think they would have to match so something was up.
I replaced both shocks (GM 19420492) and both springs (GM 20842474 Left and GM 20842473 Right). Knowing what I know now, if I had to do it over again I would probably just buy all new components (strut bellows, bearing, insulator) and build my own strut. But there was a ring (like a washer) that went on the shock below the bearing which I have not seen on any parts lists and did not come on the new strut - so I don't know what I'd do there.
So maybe I would just buy two of the Dorman 949-650 struts which were just on sale on Amazon for $368 each. That would really simplify things as disassembling the old struts took the most time and made the most mess. They also have a lifetime warranty.
Dorman lists these as a compatible replacement for the GM 20842473 Right spring so if I had too much lean to the left I would experiment with a lean correcting spacer something like this.
I did measure the before and after sit of the vehicle and also the spring rate of the new springs. I will post that next after I collect my thoughts.