Could anyone give a run down of what each of these files change?

 

I am guessing vehicles changes things like handling, but don't really know a lot about what these files actually do.

Vehicles.meta is like the handling, sitting position, sound, and etc for a car. Basically the configuration of the vehicle. Carvariations, I'm still not positive, but I think it has to do with liveries, but I never messed with anything beyond the sirensettings and light settings. Those are the configuration for the lights on the vehicle, and you really just need to worry about the sirensettings. Extratitleupdate, you don't need to worry about.

Thank you for your reply.  I really enjoy your models.  I just ask because car models have some of these and some have none.  I am guessing the more files a download includes, the more original that car or truck is going to be.

Now when I install an add-on vehicle that is dlc.rpf, the metas and car files are all included in that one file?  Meaning all metas are all packaged in the dlc.rpf file?