Can anyone help me with the process of adding new cars without losing the ones you already have? Basicly I would like to be able to add car packs without replacing the cars I have how do I do that?

Unless you want to write/code billions of handling and vehicle.meta files, the only way to do this is to get a car pack that was made for it.
For example this car pack is addon, which means it will not replace cars but it will still add them:

 

2 hours ago, Powerful God said:

Can anyone help me with the process of adding new cars without losing the ones you already have? Basicly I would like to be able to add car packs without replacing the cars I have how do I do that?

 

Thank you I will look into this I appreciate the help/advise.