If you remove the aluminum box with the cruise control circuit card in it, be careful to notice how it is mounted. I couldn't remember how mine went back in and I had to look at the other car to see how to reinstall it. Its tricky. You might wait to remove old until you get the new unit so you R&R at same time.
You don't have to remove the card from the aluminum box because rebuilt card comes inside the aluminum box. When I ordered my rebuilt unit there was a $50 core charge that was refunded when I returned the old unit.