You can basically use any textures you want without any problems, and you can use MGE for the basic stuff... like macros and MWSE.
It's unlikely you'll be able to use MGE for anything fancy
i can confirm the part with the textures. these should be ok, except for really big ones (25mb or so), like SWG skies, which my graphics card won't show *grml*
i can play with max distance and the game running smoothly, but i cannot activate mge ingame. my framerate is dead when i do (although, i have an old version, maybe the new ones work?)
Other things to avoid for weaker systems... Adding lots of NPCs in one place, high-poly objects, and mods with heavy scripts running all the time.
yepp, it's a pity, but i can't use starfire npcs ... =(