The year it's the 2000s and it means more advanced electronic technology for the vehicles, with 32-bit computers controls different part of the mechanics. The active center differential II or ACDII now boasts a faster microprocessor with extra sensors, which makes it out perform previous ACD system by a big margin.
With the new ACDII the car literally handles like riding on the rail in Tarmac mode, and in the Drift mode it will help driver perform Ken Block like power slides with the proper set up.
Recommend usage with ESC turned off or non-ESC equipped models.
Just drop the file into mod folder, press F to change between different diff mode after configure the car with active center differential.
4 modes available right now, Tarmac, Dirt, Snow, Drift
Thanks beamNG for the ESC codes.