Did the Netgear section in the readme apply to your router? If so and you followed the instructions then you should be fine with the D3, given that you may have to go through the countdowns and enter your external IP as it configures itself.
GSA is a differnt animal and needs a bigger range of ports opened to get full use of it. There is a Firewall Help section you can go through on GSA and once you have those ports open as well all should be fine.