For ADD-ON user :
you only need to replace fct.ytd file that you choose with .ytd file in (fct folder) -->dlc.rpf-->x64-->vehicles.rpf 


For REPLACE user :
just rename fct.ytd file to carbonizzare.ytd and put it in x64>dlcpacks>patchday1ng>dlc.rpf>x64>levels>gta5>vehicles.rpf

