Theres a few things you need to know.
- When you remove the factory radio, your going to lose your doorchime.
- The factory radio does not have a switched power source (ignition) that you need to work a aftermarket radio. Theres a few options you can do to get around that.
- The monsoon system can be bypassed, theres a remote turn on lead going to the monsoon amp that needs to be powered up for you to get sound out of the speakers. Other than that, the car is standard GM wiring. (I dont know the color of the amp turn on off the top of my head).
You can buy a module that will retain the doorchime and give you a ignition wire. You can buy a typical wire harness that plugs into the car and wires into the factory radio, but you’ll need to run an ignition/accessory wire from under the dash to the aftermarket radio. You will lose the doorchime with this option. And lastly, you can buy a t-harness. The factory radio gets mounted in the trunk, and gets wired in with a harness that extends from the dash to the trunk. This harness will let you add an additional speaker to use as a doorchime, but you still need to run a ignition/accessory wire to the aftermarket radio from under the dash.