Question about CX-7 Navigation System Parts

2021 RDX A-Spec
I have the oppourtunity to buy the OEM navigation head unit for my CX-7 on the cheap (basically, this part). However, I've been told that I'd need two additional parts to make the navigation system work: 1) The GPS receiver, and 2) The navigation drive.

So I ask these two questions:

1) What utility will the head unit have without the navigation drive connected? Will I at least be able to use the touch screen stereo controls, etc?

2) Where exactly are the navigation drives located on the CX-7? In the glovebox?

CX-7, Electric Blue sport with Tech
The head unit may not even turn on with out the DVD drive. It goes under the seat. I would say it won't work cause you need to clear the first screen that comes from the DVD drive before you can use the touch screen stereo controls.
By the way the touch screen controls are not very cool at all. Look around for the DVD drive as many people are taking them out of the cars cause they are not smart enough to figure out how to add an ipod to it. It sounds dumb but it is true.
Good luck.
Mazda CX-7 2008 Sport Turbo
too bad I didnt read this thread before buying the used head unit :(, is the DVD unit too expensive? can a regular DVD reader work with some mods?