No, you can ditch the POS Bose system.
Your options are:
1. Remove Bose, order new fascia, fit new fascia and new deck.
2. Fix Bose, install band expander.
What you can't do is remove the Bose, and cut the existing fascia to fit a new deck. If you do that your air con won't work. That's why you need the new fascia, it gives you the air con control circuitry.