And also there's some more progress! On two cars to be exact. I don't have a picture for the first one, but there was a simple code change to the Old Vortex. So whenever you see the vehicle name
Vortex Old, that's the update, the datablock's names have been changed as well to seperate datablocks from the old and new Vortex.
Basically what i'm saying is that the Old Vortex in-game is now known as Vortex OldBut for the Modern Challenger here's some pictures

On the beta Modern Challenger, in the before picture, that white part in the interior was part of the actual car color. That material blank has been removed and has been replaced with blankglow (The colorable neon material) on that mesh, and joined with the nodes for the parts in the Lights Category shown in the After photo.

There was a shadow glitch where the seat parts wouldn't cast a shadow. That has been fixed really easily. I might remove the option where you can choose seats. It's getting kinda pointless all of a sudden.

If you saw the window in the video, the material is a bit lighter.
That's some good news, but there's also some bad news known as
KNOWN BUGS

The window material doesn't seem to comply with the Seat parts no matter if A or B is selected. It works although for the non-parts (The interior walls and dashboard for example). Another weird thing is it seems to comply with the interior neon node from the Lights Category parts. That's another reason why I want to get rid of the option of changing seats.

If parts Sun-Roof nor Default is not selected. The roof seems to not to cast a shadow.