Help!! Im trying to replace the original Alpine stereo and cannot seem to figure out how you access the back of it. Is there a panel you remove or ???

In your locker you will need to remove the carpeted ceiling area. This should be held in place by a few screws al the edge of the panel. If you have the hanger rod in the locker you will need to remove it as well. You may need to feel around for the screw heads. It's a very tight fit! Once it comes out you'll see they used a muffler strap type metal strap to support the back side of the stereo. Be sure to have some extra stainless screws around when you re-install the ceiling.

My Stryker is set up the same way.
I have a couple of white plastic "buttons" on the carpeted ceiling panel that covers the screws. After removing them, the panel can be removed and I have access to the stereo.

Thanks guys! I am in the middle of installing 2 amps, a farad capacitor, 6 speakers, a sub and new deck and was stumped on how to remove the old deck--now I can get back to work. appreciate it!