I can't help you with the Bose amplifier question, as I don't know that system too well. I can tell you that the dash piece isn't too hard to take off. It is all one piece. Start with a screwdriver covered in electrical tape (to prevent scratches) and CAREFULLY pry the panel that surrounds the radio, climate control, etc.) out. Go section by section until you have the whole thing loose. Then lower your steering column to ease in removing the piece. As I said its one big piece which extends to the left side of the steering wheel.
'02 Aurora 3.5, factory NAV retrofit, CD changer retrofit, Philips Xenon lights. '96 SE: Gone but not forgotten :( Oh yeah, and a few other toys.