Im pretty sure caddilac was using a form of magnetic dampening in the 90s(edit: i was thinking of the 2002 STS)
from the autoguide article in your link
this was in the comments.
Cadillac did develop the technoloy for use the 2002 STS, under DELPHI, which GM owned the control of. Bejing West Industries purchased Delphi's chassis division when it was dismanteled. The MagneRide system was a byproduct of Delphi's work with LOTUS on it's then active suspension system for F1 (which GM also owned at the time) in the late 80's early 90's.
Now you know. Cadillac was the first car to utilize the magnetic suspension system. which is a patent protected system, that all manufactures pay to utilize in thier automobile. Fiat, GM, Audi, Honda all pay BWI for the technology, But Cadillac pioneered its first use partnered with Delphi/Delco. Active suspension in its modern form would itself be traced to Lotus F1, (which is a complety different system) however many manufacturer's were developing semi-active adjustable dampers and air spring systems since the late 1970's.