WELCOME TO IRONWORKS
You can install ToB on top of SoA (it's an upgrade after all)
BUT
I'd advise you to remove any mods and even Baldurdash fixpack (there is a pre-ToB uninstaller on Baldurdash's site).
Then install any official patches.
Then ToB
Then any official ToB patches
Then Baldurdash
Then MODs
You can seamlessly continue to ToB after SoA has finished. Where you'd normally get back to the main menu after the extro a new chapter will now start.