here is what will happen when you install speakers in doors:
i wash my hands of that job, was done by the previous owner. but its one of those "i realllllllly cbf fixing that" jobs.
you will be amazed at how many times you kick that speaker by accident. then every time you slam the door it loosens/breaks the speaker a bit more. over time the screws will come undone, the mesh will go missing then you will kick the speaker cone, then one day itll just fall off onto the ground when you open the door. itll probably be raining so it will fall into a puddle of water. also if your window felt leaks a little bit (which every holden does) then you will need to seal the back of the speaker cone to stop water getting in. also you will need to drill a hole in the door and the A pillar to run a wire to it.
is it pretty straight forward to do? i have some 4" speakers in the front kick panels but you cant hear them to great so i might go with the vr/s door pods and stick some 6" in them. plus the door pockets would be handy for putting stuff in