The transmission you're looking for might be more commonly known as a 32rh. The TF 999 had no provision for a crank position sensor on the bell housing, which you will need. The 32rh is a TF 999 with a spot for a cps. You can make a 999 work, but it'll be a lot easier with a 32rh.
Good call too. I liked the way my 32rh worked better than my current aw4.