Carcols issue

[Haynoob]

Hello,

I am trying to replace the default police with this mod: https://www.gta5-mods.com/vehicles/els-1986-chevy-caprice-9c1-los-angeles-police-dept#comments_tab

The mod has an carcols.ymt which is suposed to replace the original one, but it's the entire file. If I want to add another mod with carcols it will replace the entire thing again and loose the one which was replaced previousley.

How can I identify what specific lines have been replaced or added so I can manually add them to the original file?

[Haynoob]

Also, where do I install carvariations?
The file specifies update/x64/dlcpacks/mpchristmas2/dlc.rpf/common/data , but I think this was the last dlc at the time of release.

I'm not sure this is right anyway because the model files were not in the place where the file specified.