Once someone creates a tool that can modify model/texture archives so we can replace them with our own. No telling how long that will take. I'm not a software programmer so I'm not sure what exactly they need to figure out before they can start working on writing such a tool.
When do car mods come?
And yet the model format is different which we will need importers exporters/Covnerters for PLUS the Damage to cars Might be poly deformation if so its going to have to change some ways people model Vehicles so they deform Correctly on damage.(Btw i am a 3d Artist)