I have a pair of used active suspension rear shocks for a 1993 Cadillac Allante.
The car had 24000 miles on it when I replace with aftermarket Passive suspension because the "Service Suspension" light was on.
There is no aftermarket for these "Active Suspension" shocks, and NOS was long ago eaten up. However I was told that there are companies rebuilding these shocks, but have a very expensive core charge. You can buy these to rebuild yourself or use as cores, and/or replace your higher mileage springs. $100 plus $50 ground shipping to lower 48, or pick up at my shop in Beasley, TX.