I've looked and haven't found an answer.
I know that premium 5at autos came with rear ac that's located in the center console. I have the base 5at model 03.5 to be exact. Just wonder if it's possible to put in a rear ac on my car, I've been thinking about getting an auto start and I've been carrying my family around. What parts would I need besides the center console with vents and is it worth it? There's 2 gsedan at my local lkq about to get some spare parts for my car.

 

Very hard to tell from the service manuals:
http://www.nicoclub.com/FSM/G35/Sedan/2003/
but it looks like there is a 2nd vent pipe running through the center console to that "rear vent". As in, it's not the same as the "rear floor" vent pipe which runs beneath it.

The book shows that manual transmission models did not have the rear vent but autos did. Odd that it was only the premium package 5at. That makes me think you would have the room for it but it would probably take a LOT of parts. I would think you'd need to have a different shroud for the main heating/cooling unit behind the dash with the extra output, plus maybe an extra air valve, plus the new vent pipe, new center council, etc... and who knows what else. Seems like it would be a very complicated mod.

To keep the family comfy I would recommend cranking the system in "floor" mode and making sure your rear floormats are not covering the vents.

 

I have the rear vent in my car and it's weak. I don't think it's worth the effort.

 

I would second that. It's pretty weak. The front center vents directed to the rear probably have better output. Not worth it IMHO