Right now it can only insert, but won't take items out of it's connected inventory.

I can see two steps to make this work without affecting performance noticeably:

• Have it only check one slot per tick and go round-robin (instead of the whole inventory at once)
• Have it only run itemstacks that have changed through it's filters

Optional: make the extraction a GUI option that's disabled by default too - that way users can specifically enable it for their "input" chest of whatever storage mod they're using