In my case, I have Red Dead Redemption GOTY and I manually installed it on HDD. This week the digital version is 75% off on xboxmarketplace. I kinda like it that I don't have to insert discs every time and I don't need to worry the discs will wear out one day.
While if I buy the digital version, do I have to uninstall the GOTY version first? The GOTY version does come with some extra perks (for example, Solomon’s Folly single player gang hideout, which is only included in GOTY for xbox360). If they can coexist, I want to use the digital GOD one for zombie and multiplayer. HDD space is not my concern here.