Hey @superqwerty11112,
Those packs you referenced are not a replace but add-ons.
You will need to download replace vehicles that are ELS for it to work that way.
I noticed on this topic you referenced that you had :
LSPD & Friends
SAHP & Friends
LSSD & Friends
Those specifically caused me game to have those issues you are having. So I would recommend removing them and try installing this instead:
This is a replace so it will replace the current cars that are actually in the game:
Police
Police2
Police3
!This pack is ELS also!
This one will replace:
Sheriff
FBI
!This pack is ELS also!
Let me know if that helps you out!