I'm going to assume 2 things:
1) the g6 has room for a double DIN head unit and you want to put in a DvD monitor/receiver the size of a double DIN headunit
2) the converter kit that you will need fits in the double DIN slot, but only allows a single DIN after market head unit because of the extra info display module

I would either install a single DIN dvd player with a motorized screen that pops out or cut up that adapter so there's just the section with the info display left, and mount the info display somewhere else...probably out of sight because it kind of looks like shit. That you way you can still have a info display that you can check but a full size in dash dvd player as well