[AudiA4B6US]

The Symphony and Nav+ need two antennas, (HF and ZF, main and diversity) for best reception, the Concert has only one antenna. Without diversity reception might be poor. If you have a Symphony now, see what happens when you unplug the ZF connector, in an area with good signal, you might not even see a difference...

 

[AudiA4B6US]

Bose is just a set of speakers and an amplifier connected to the HU's pre-out, has nothing to do with the antennas. The XM antenna is connected to the sat radio receiver somewhere back in the trunk.
They don't have sat radio in Europe and the Kufatek adapter may be missing some wires. I have the same (Symphony, Bose, XM + OnStar), will see how that works when my adapter arrives...