Yeah, and now he's just copy pasting the post about opening ports from the bloody forum. I already mentioned in the ticket that the ports were open and uPnP was set. Oh, and he didn't even copy paste properly, only copied from the regular post, not from a quote screen, so the links are broken >_>
Steam support got back aswell, just said to update DX drivers and VC++, etc. and restart PC, if that fails contact Atari >_<
EDIT: I'VE GOTTEN IT WORKING!
Used some sort of 3rd party search tool to search entire PC for and instance of TDU2/test drive unlimited 2/atari, and it found steam files, TDU1, and the hosts file in System32, so I looked in the hosts file and found out that the TDU2 patch server was being redirected to the home IP (127.0.0.1). Deleted the entry, et viola. She works. So far. Updating anyways.
Also replied to Atari again.
"It won't let me sign in to the Atari site to close the support ticket, but I've gotten it working, no thanks to your copy/pasting. If you could close the ticket, that'd be great, thanks for nothing." Maybe they'll learn eventually.