The Polaroid Cube WiFi doesn't seem practical for a dash cam application. I would suggest mounting the small camera on the back of the rear view mirror, but the power supply for the camera is on the back so that won't work. It has a magnet on the bottom so you could put a piece of metal on top of the mirror, but again that won't work.
You could add metal to the bottom of the mirror and put a magnet on top of the camera to mount it under the mirror.
I read some reviews on this camera and the picture quality doesn't sound impressive. Several comments like "cute" and "adorable" were mentioned along with it is marketed towards kids.
11GX460, if you are looking for an impractical cute and adorable kiddy camera for your GX, I say go for it.