How to install:
1) Navigate to Documents/Rockstar Games/GTA V/Profiles/(your profile)
2) Copy and paste SGTA50015 and SGTA50015.bak (you may have to rename or replace these if you already have files with the same name) into your profile folder
You want to Edit your Save Game yourself ?
Then checkout the Save Game Editor for PC whitch allows you to do manny usefull thinks like Edeting your Weapons, Vehicles, Cloaths, Missions and you can even add God Mode.
PICTURE OF THE TOOL