I want to put 6.5's in the rear side panels of the Civic Si HB. I know that Honda has a OEM grilled panel that serves as a combo speaker grill & rear side panel sold for $18.16 ea. side.

Question is:
Do I need a bracket behind these grilled panels to hold the speakers & do I need some sort of seal/speaker hole for each side?

Attached is a schema for the rear speaker bracket from Hondaparts.
Just not sure what alls I need. Any help would be appreciated. thanks!

What parts in this diagram do I need to install speakers in the rear side panels?