Ceiling speakers

Basically remove every piece of trim and the way they're layered on top of each other you have to start at the door sill panels.

Then the SRS airbag labeled plastic caps get pried and popped open and pulled off after that it basically falls down on its own.

It's the trim and those couple of squares that hold it up.

 

easiest way to make speaker mounts for locations like that is 3/4" MDF and a jig saw. That's pretty much what you'd get if you bought pre-fab from Crutchfield or pretty much anywhere else. For 2 6.5" speakers, a 2'x4' "project panel" from any big-box home store (HD, Lowes, or similar) would give you enough to try several versions.

With a sub that big already runnning in that small of a space, you might not notice the difference from having another pair of 6.5" cones back there vs just killing the rear channels altogether. Biggest sub I ever ran in a pickup cab was a 8" Bazooka tube in the 97 Tacoma 5-lug I had back in my 20s.