Gog.com downloader doesn't work. So I tried manual downloading for the combined bonus content.
I was able to dl manual but rest of the items I get the error message of

403 Forbidden

Has anyone able to get all the bonus content of Pillars of eternity?

Here you go friend:
https://www.gog.com/forum/pillars_of_eternity/gogcom_downloader_has_stopped_workingcant_download_combined_bonus_content_pack

Thank you for the link. It has fixed the download issue for me.