I own vanilla oblivion and am thinking of upgrading to SI. However, I hear that this will possible ruin some of my mods, and savegames. I can imagine the mods that have separate versions for SI and vanoblivion will be affected, but what about other mods and savegames?

yes and no some mods require SI due to either textures or meshes the only possible i have found is with Knights Of The Nine DLC nothing all SI does is change some IDs that makes KOTN break ( very rare) some mods try to fix it but most people just live with it and i played the KOTN loads of time ( messing around with the knights inventory) and no crashes or bugs

i cant think of any more mods that really upset your mod or savegames but i would back them up just in case

Col John Sheppard

Knight of the Nine issues really is dependant on what version Of knights you have. If you downloaded, then upgraded to SI, yes you can have issue, but if you have a rather newer version, AKA Game of the Year Edition, it works fine.

As far as other mods, I have a lot running at once right now with the SI. The only thing that you really want to avoid is taking Companion Mods into SI, or so I've heard. I've done it and nothing has happened so far, but I might just be lucky. So just don't take you companions there and you should be fine.

Remember this is something like doing a make up and after pasting the base all over the work.

patches and the greater mods and plugins should be installed first. So maybe and depending on what you have installed things may works well, go wild or worse, seems OK and go wrong later when may be harder to isolate the troubles.

since i given up oblvion now but still use it to find problems for other people but i didnt update my SI when i got it and it works fine no problems but the only mods that i can see people have problems with is anything the messes about with SI main quest

Col John Sheppard