What follows is a number of generic tips to remove your car stereo headunit (the part that you the user interacts with) from your car without tears (without damage to you, your car, or your headunit).
Step 1: Before You Begin
-Get directions on how to remove the stereo from the DIY section of the car forum for your specific make/model of car (I happen to have a subaru brz, but have tried to make this diy somewhat generic).
-If their is a security code for the stereo, make sure you know it, write it down before you begin.
-If you love any of the settings (EQ, radio presets, etc.) write them down before you begin.
Step 2: Use Blue Painters Tape to Protect the Interior Trim of Your Car
Headunits are usually installed in stamped metal cages with sharp edges. These scratch plastic interiors, rip leather, and can cut your arms up. Protect these things.
Step 3: Protect the Screen With a Soft Cloth
Drape a soft cloth over interior protrusions (such as the gear lever or handbrake lever). This prevents the headunit's screen from being scratched or shattered during removal.
This is especially useful when some of the connectors on the rear of the unit require a large amount of force to pull loose. When these slip free it is possible to slam the screen into the interior of your car causing damage.
Step 4: Be Gentle With Bolts and Screws
Be gentle. These aren't super hardened bolts. They may strip easily. If you feel extra resistance, back the fastener out and make sure things are aligned properly. Fixing a stripped fastener or a messed up hole will take a lot longer than being slow and careful the first time.