Do you have new speakers to put in? Or do you still want it to play through the bose amp and speakers?
When I did mine I just tore everything out and put all new in. It was cheaper to do at the time than buying all the adapters and not having to run wires from the headunit to the bose amp for every speaker.
The easy way would be to get the adapter. I ran all new wires to the headunit when I did my install, took a while.