Mike,
I don't have the wiring diagrams for either of the XM modules. Once the new one arrives, I will have the actual modules side by side, and compare. I'll look specifically for the inputs you mentioned.
One thing I've seen mentioned on the boards is that the XM module for the Symphony II system is recognized as being in place by the RNS-E, however you can't switch channels to check and see what the Radio ID is, and register it. The sound comes through, but other communication between the RNS-E and the XM Module does not work.
I was not aware that the XM module had inputs for the CD Changer. I might just go ahead and buy one, if is going to be that easy to plug into. I will be losing the on-board CD Changer, so might as well put one in the trunk. Not sure I'd put the iPod back there though. Most definitely another good solution to have nonetheless.
The whole setup is expensive. I never mentioned pricing on the thread. But I assure you that nothing about this car is cheap. If you plan to keep your car past warranty, you might be in for a rude awakening.
I am sure that with a bit more money I could have had a better setup, sound and video wise. However, my concern is to have it look as stock as possible. Being that the center of the console is an extremely visible item, I did not wish to mess around with it much. Even though the system is more expensive than probably worth, to me it is worth it. I think the adrenaline rush of wanting to tackle this project myself, sort of subdued the pain I felt in my pocket.
I have other more expensive projects lined up. Just wait and see.