When you need to upgrade your rear 6X9 speakers in the back, there is a little trick in order to swap them out properly.
Small flathead screwdriver
Step 1: Remove the SRS housing on both sides
Using a small screwdriver, pop the SRS airbag screw cover off. Try not to scratch the plastic, it should come easily. There is a single 10mm bolt that needs to come out behind it. Once its out, carefully pry the top off and follow on down the housing. There are two clips that should pop off and two hinges on the bottom that just slide out once it is on its side.