Is there any reason to have both the original repack and Sunshine repack on a computer at the same time? Or is it okay to have the Sunshine version only? Asking because a lot of the cards I download ask for the HF patch for the original game and not Sunshine, but I have Sunshine installed, which has some compatibilities.
Normal game has more mods.
You can convert KK game to KKS as long as any mods they use are also installed on KKS (if they exist AND are up to date). But not the other way around.
KKS as a different gameplay to increase affection, a few extra personality and some exclusive map and H position (although Studio mods bassically negate map and H scene exclusive).
So, if you want to play the game and not toy a lot with the studio, the best is to keep the version you prefer to play.
If you want to mod mod mods and creat and enjoy shared studio scene, go for the original KK (do note that keeping up to date with all the most used mod and map easilly triple the game folder size).