This example for Lenny’s Mod Loader shows you how easy it is to make any vehicle an addon vehicle. The game’s default POLICE2 will be added again as POLICE6, including a custom display name when entering the vehicle in-game (“My Car”). If you wish to add a different vehicle as POLICE6, simply replace the files in the “stream” folder. Ideally you create a new LML subfolder for each new vehicle and modify the stream and data files accordingly.
Credits:
LMS