I also wanted to know what the difference between the WG511T & WG511TGE cards was.
I asked Netgear support this question, first by email, then by phone when I didn't get a response that quickly via email, at least initially.
When I called their telephone support line, I was told that WG511TGE did not exist as a product, only WG511T. I tried to explain that various websites mentioned one or the other or both, but the answer was repeated. I gave up at that point.
However, I eventually did get a bite on the question I had emailed in, and after I provided some websites showing the two product/manufacture codes, I got a satisfactory response. I quote:
"There is no difference between WG511T & WG511TGE. GE it means German Edition."
So, there you have it. As to why there is a specific need for the different product/manufacturer code, your guess is as good as mine.