Installation guide:
Add-on:
Run Open IV and enable EDIT MODE
Go to path Mods/x64/dlcpacks and drop parslx folder into it
Then go to path Mods/Update/Update.rpf/common/data and right click on dlclist.xml and choose EDIT.
Paste <item>dlcpacks:\parslx\</item> in it. 
Spawn name in game : parslx

OIV:
Run Open IV and choose package installer in the items.
Find parslx.oiv in your pc and choose it.
Install it and choose mods folder.
Spawn name in game : parslx

Replace:
Run Open IV and enable EDIT MODE.
Go to path Mods/x64e.rpf/levels/gta5/vehicles.rpf and find and replace car files.