A G2 roof skin with OEM moonroof would be awesome! It's more than likely that you would have the only one in existence. It is important to use the G2 headliner, as the moonroofs are located in different locations. You will have to pull front and rear windshields to get to the spot welds at the ends of the roof skin. There will we spot welds along the door seam area behind the weatherstripping and some more along the roof channel, behind the doors. You want to drill all of them, only as deep as the outer panel, so that the panels left on the vehicle aren't full of holes. Repeat this procedure with your G2 roof skin. You may need to use an air chisel in order to seperate the panels, after drilling all of the welds. Use a quality weld-thru primer on all of the bare metal areas that you will be welding. Oncle you have the panels lined up, you can MIG weld the holes left from drilling and grind down any extra material. Prime, then paint. This is a VERY short description of the work involved. Let me know if you need any other assistance, I will do my best to help though I currently have very little free time. I hope your project goes smoothly!
-Joe Michael