This video explains the updates to the UAC Rig in the 2.4 version put out on 25th Jan 2021.
The video also answers a common question: Can the UAC Rig be used on vehicles with different sized front and rear wheels? Yes it can.
[ v2.4 ] - 22/1/2021
1) Bug fix: Steering wheel now moves when car auto steers on curve paths.
2) When using multiple cars, setting your active rig with the long top button on the UI previously required you to select the root_ctrl. You can now do the same job by selecting the TopNode which saves sifting through groups in the outliner.
3) Full version users now have additional Maya scenes included that contain no chassis model and none of the joints needed to support the springs, sway bars & boots. This is great light-weight option for game integration and background cars.
4) CH button added to UI. This button indicates if you want to load a rig with the chassis model or not. It is set to on by default.