Open OpenIV>update>x64>dlcpacks>patchday3ng>DLC.RPF>x64>levels>gta 5>vehicles.rpf and replace the files from the archive.

If the model doesn't work set it to update>x64>dlcpacks>mpheist>dlc.rpf>x64>levels>gta 5>vehicles>mpheistvehicles.rpf and replace the files from the archive.