Use OpenIV and extract dlclist to your desktop from: \Grand Theft Auto V\update\update.rpf\common\data\dlclist.xml
Open dlclist with notepad, and add this new line:

dlcpacks:\r8\

Save it, and replace the original dlclist with this one using OpenIV



Use OpenIV and extract extratitleupdatedata.meta from: \Grand Theft Auto V\update\update.rpf\common\data\extratitleupdatedata.meta
open it with notepad, and add theses new lines:

dlc_r8:/update:/dlc_patch/r8/


Save it, and replace the original extratitleupdatedata.meta with this one using OpenIV