Everybody and Anybody - SOS!

I was so excited to land my first Porsche - very clean very low miles 2004 C4S cab!! Everything is awesome! Except the bleeping radio! holy cow!

I live where SAT Radio is a must. In an attempt to get ( choose one / all): SAT Radio, iPhone, Bluetooth, a modern head... i have found out plenty - but not much of path forward. Can we map out this problem for me ( and maybe others) to Fix?

It has something to do with the MOST bus that Porsche went with. There are fiber optics cables from the head to the amp. Amp is matched to the speakers? not sure what that means. There is no switched power line behind the dash. I found a harness that is ~$650 (MOST HUR) that will connect 2 radio manufacturers products (ALPINE and KENWOOD) to a 2004 system - EXCEPT MINE!!

It seems I have the 'perfect storm' - 2004 with the upgraded BOSE system. the harness will not work with that exact combo!! so if i had a different year or the standard radio package for 2004 i would be better off. UGH

I have been in touch with the high end stereo guys in town ( they are who the OEM S in town use ) and they say they would have to run new wire for the speakers ( they think it would take up to 1.5 days to take all the panels off and run new wires) - but still not sure how to 1) find a switched power line 2) how the antenna will connect 3) where to put a SAT Radio antenna.

Good news - I did find one potential solution - NAVTV ( the MOST HUR guys) says they can wire an AUX plug into the radio. thats kind of a solution.

Here are my questions:
1) is there a switched power line behind the dash - and how would I ID it?
2) What is the deal with MOST?
3)DOES most really tie the whole car together? - i mean electronically.
4) How hard is it to 'Start Over' with a new head unit speakers...
5) is there room behind the radio in the dash for a standard 1 DIN?
6) is there room to move the AC controls down and put in a 2 DIN?
7) Is there room for amps of any size?
8) What is the CAN bus?

Thanks in advance for any input / help. hank