Thank you for your answer. With locally I meant to add the vehicles to GTA 5. I just tried it again with the mod in different folders, but without success. I'm not sure which folder you mean by "server folder".
At the moment my structure looks like this:
- server-files
- bridge
- client_packages
- some node.js files
- dlcpacks
- rs6
- dlc.rpf
- dlcpacks <-- for testing
- maps
- packages
- some node.js files
- dlcpacks <-- for testing
- plugins
after a test I remove the new folders again. I had also tested it with the Shelbygt500 from the test pack and 5 other vehicles - without success. So far I have not found a Rage.MP server that had mod vehicles.
Unfortunately, I find no official documentation on this topic.