Install all models into update/x64/dlcpacks/patchday16ng/dlc.rpf/x64/levels/gta5/vehicles.rpf

Install the two textures (plate07 and plate07_n) to x64e/levels/gta5/vehicles.rpf/vehshare.ytd. Import the two files and save. This is required, or else the license plates will not work.

Install the carcols.ymt to update/update.rpf/x64/data

Lastly, install carvariations.meta to update/x64/dlcpacks/mpchristmas2/dlc.rpf/common/data