Upgrading the base roadster audio and need some help with sub location

Quartermaine

I am looking into upgrading my base roadster's audio system and have some questions regarding sub location. I have seen member jtgarza3 with this setup and ddanis60 with this setup. Both looks great but what I would like to do is to put two small "sub" (same size as the Bose?) where the Bose puts their in the touring model, like this. I took the pleather apart where the tonneau folds in and saw there are two holes covered by two aluminum panels with screws holding to the body. They look like 6x9, not too sure. I also took the trunk lining out to take a look at the back of the aluminum panel. It doesn't look like there is a lot of room in the back.

My question is whether this is doable. If so, what brand/model I should be researching? Any recommendations? I am not looking for anything bass-y but just want something a little punchy and adds to the music but overpowering it. What do you think? Good idea or total waste of time and money?

Thank you in advance for the help and any suggestion is much appreciated. Thanks.

Additional information. The HU will be replaced. Front speakers will be replaced with Focals. An amp will be added to drive the speakers and woofers.