Yes, Lou, I'm talking about the factory installed unit. I swapped the XM unit that came with it for the Sirius (part 999U9-AS006). I didn't take any pictures of the install, but it's been working flawlessly since Nov. 2008. This was before the merger and my wife made it all of three days on the XM trial before demanding that I do something. I found some info on a search that showed a successful swap on a 2008 Titan, so I gave it a shot.
I was able to take a photo of the jack on the XM receiver. You can see the part on the top that is the "key" for the antenna. This is what keeps you from intermingling XM & Sirius. All you need to do is shave that piece down so that the female input is round(er). You can then plug the XM factory antenna into the Sirius receiver. Edit: I can't seem to insert the photo, so here's the link: http://www.flickr.com/photos/3...33968
If you do decide to go this route and you need to call a local parts department, tell them you need the Sirius unit for a 2006 Altima with the Bose system. If you say it's for a Rogue, they'll tell you Sirius isn't available...but that's because they stopped offering Sirius after 2006. Lucky for us, the parts are still the same.
The unit cost me about $200 US and then another $15 to swap the subscription. It was worth it for me at the time to have a clean, integrated install.
Hope this helps. Let me know if you have any other questions.