That makes sense, and I'm a lot happier now that I know you can install more mods (as long as they're compatible).
That being said, I installed TooManyItems (1.1 version, as needed), but it doesn't work. I mean, it works, as in I can see all the items and stuff, and all the special modifications and stuff made special for it for Technic Pack (I think), but it doesn't work as in the only thing I can't do is spawn items.