Hi Fantam,
Good question.
If you update the downloaded asset in your vault it will NOT carry over to your project.
I’m not sure of any ‘perfect’ way to apply the update to an existing project.
First, you’d want to make a backup of your project incase anything goes wrong.
Then, I think if you ‘add to project’ again it will overwrite the older asset files with new ones (This could be a problem if you’ve changed them, as your changes would get overwritten)
Another option would be to create a new project and add the marketplace pack there. Then you could have both projects open at the same time and compare differences. (Knowing what the update changed/fixed/added/removed will be helpful here) You could then move/overwrite specific .uassets yourself)
Hope that helps.