The only Mark VIII that got the Shock Absorber Actuators were the 93-94 models..
Even though you could find the Shock Absorber Actuators on the 93-94 Mark VIII's..They didn't use (ARC) Automatic Ride Control..
They used (SDC) Shock Damping Control..
What you may ask is the difference??
Like the (ARC) system found on the early SC/XR7 MN12 models..An electronic module controls 2 relays that provide power to the Shock Absorber Actuators..
These actuators vary the shock absorber's internal damping valve size..
However, unlike the MN12 system..Only the rear shocks are variable, and the brake pressure is the only input signal used to trigger the system into firm damping mode..
The MN12 (ARC) system can be manually adjusted from "soft" to "firm" mode with the push of a button..Both the front, and rear shocks are adjustable as well..(not indepently)
Tokico was the original manufacturer of the Shock Absorber Actuators found on the MN12, and 93-94 Mark VIII models..
They also manufactured the rear shocks that were found on the 93-94 Mark VIII..As well as the front/rear shocks that were found on all MN12 that used (ARC)..
Whether you replace the rear shocks with factory replacements, or Tokico Illumina's..
You probably won't notice much of a difference between the two..Considering how the (SDC) system works on the Mark VIII..