[demick]

If you are lucky, your new Alpine will use the same wiring harness connection as your old one. So you should be able to pop off the bezel, slide the removal keys (that came with your new unit) down the sides and remove the old deck. Disconnect the wiring and plug it right into the new deck (assuming the plugs are the same). Slide the new deck in, install the bezel, and you're done.

As I said, if you are lucky and the plugs are the same, it should only take 15 minutes.