The only thing is to make sure that if you add thes you put them in the rde folder so they essentially 'overwrite' the originals, if you want to add completely new vehicles with their own name i recommend looking for the mod police and ems as addon, it will allow for a greater variety of vehicles across the game, if you use that with say custom backup locations by PNWfan then you can have your new models respond as backup for you as well no matter the name it just needs setting in the ini file