Installation:

1: Install this mod:
https://www.gta5-mods.com/vehicles/vapid-bobcat-hellraiser 

2: Extract the "bobcat_sign_6.dds" file

3: Using OpenIV with Edit mode enabled, add it to "E:\SteamLibrary\steamapps\common\Grand Theft Auto V\mods\update\x64\dlcpacks\algobobcatc\dlc.rpf\x64\vehicles.rpf\bobcatc.ytd"