I played many times BG and BG2 with several mods etc. But i have some concerns about gog version. Can you answer these questions please:

1- Bg, Bg2 and all the expansions is updated to last official patches? Or do i need to find and install some patches?

2- Are all the mods (like easy tutu, widescreen, unfinished business etc.) compatible with the GOG version?

3- Is there a difference between GOG version and CD versions of the game regarding the files or folders?

1. Yes they are fully patch

2. You can find here in the forums lists for mods that are compatible with GOG version.

3. From what I can see and hear here in the forums only difference is that you don't have to use your CD's, also GOG versions are DRM free which is a big plus for me.