If I buy GTA V with a key via social club, can I then add the game to steam?
Solution 1:
While you can add the GTAV.exe file as a non-steam game shortcut, it will just be a shortcut.
To get the proper steam version, you will have to buy it either from Steam, or buy a Steam key from a third party reseller (most, however, don't sell steam keys for GTA V).
If you buy the Steam version, you can also play it as the social club version without running steam, but not the other way around.