Mazda6 Audio Inputs
I Just got a Mazda6 as well. It has the in-dash 6 cd changer, but is not the BOSE system. I don't know the answer to your questions yet but I'll post what I do. Hopefully it will all work. Best I can tell from research, the following is true:
1) The Sat button uses a 16-pin connection in the back, which works with either the Mazda Sirius system, Mazda iPod system, or the
AudioLink iPod system. But not all at once.
2) The Mazda iPod system generally has gotten bad reviews. The AudioLink iPod system is better and also includes a regular audio jack for other inputs.
3) There is a Mazda
switch available ($113) that lets you use two 16-pin connections, allowing you to have Sirius integration and iPod integration. I haven't found anyone that has tried it on a 6 before though. Mazda corporate says it won't work on a 6. If it worked, the Media button would control the iPod and the Sat button would be Sirius.
4) The Media button is normally used for a
tape deck connection I believe. If you want,
AuxMod by Sylfex is made to plug into that special connection and provide an audio jack. While this isn't integrated into your steering wheel controls, it is the simplest way that I have found to add an auxilery input to a Mazda6. It's also only $60.
So, hopefully that helps explain what is going on. This
video shows how to take your dash apart too.