Radio Wiring Help

[nola mike]

just drove the new s home from south carolina last night. i have the bose "premium" sound package (no rear speakers with this?) and a sony aftermarket head unit with xm changer built in. a couple of questions while waiting for delivery of my bentley:
1. the "bus in" input of the unit is occupied--does anyone know if this is for an xm control box of some sort? i'd like to plug my mp3 player into that slot...
2. i got no AM reception, and fairly crappy FM reception. prior experience has told me that this is from a blown/not powered antenna amp. does this car have an amp?
3. there's a lonely, unconnected blue/brown wire from the car--anyone know what this is? illumination control, antenna amp power lead maybe?

thanks!
'02 Boxster S Silver/Black