The program name is cmx "viewer", that means you can't do anything but see car models and skin you previusly made in other programs (Photoshop,paint.net,gimp etc), if you want to make skin there are plenty of tutorials online
It was like 8 years ago or something, I was looking for a free simulator with low system requirements and found this game. 3 years later I created my first account here. Good times
Just for comparison here are screenshots of mods and original file.
Note 1 - This mod allows you to change Windows texture, steering wheel texture etc
Note 2 - Ignore slight diffrences between pictures, its my fault.
#1 Interior
#2 Rear
#3 Side
Sorry but this doesn't make any sense, what lowest licence you are talking about (And you mention them upgrading to s1 or s3)? Also what kind enhancements? Currently demo players can mod XRG with tweaks to fit XRT, XRR etc and it seems like nobody cares about you if using tweaks, but if you use vob on the other hand..
If you don't like something doesn't mean nobody likes it , from my experience vob mods change only looks of the car, specs of the car doesnt change a single number (Used a wheel, mouse to test it), also You want cars from devs? Don't install Vob mods / texture mods / anything then. Keep the game stock