Found the XM. Thanks for the tip. It was there all along. Nicely hidden, at least better than the Lojak system. It was not bad to remove/replace the XM module. A bit of a trickery really, to get it out of it's cuby-hole.

As for the antenna fellas, all the wires within the roof liner and coming out of the antenna are male connectors. The wire I got also has one female at one end (for the RNS-E), and a male at the other end. Sorry, but male-to-male was not a good idea here. Figured, since I'm removing the Navigation module from the trunk, why not use the female connector that is there, and plug my male into it. That worked.
Wiring it all the way to the front was not fun. Could not get my rear seat bottom to be removed. Check with Bentley manual and all. Heck, I removed the pillar lining (side and top of windows), and routed it to the front. Bad thing is that there is an area it crosses under the airbag, as I moved the wire from inside to outside. This is not a permanent solution, but should be okay for now, until I get the seat issue resolved. It is all working, including XM radio.
At first I was worried as the Navigation portion would not update my location as I was moving around. But after driving around for 30 minutes, it was all fixed.

Pix and story to come.