We never quite got that far. Only a handful of us have done the swap so not much data to go off of. Best bet is to try and hunt one down.I'm trying to add BT to my 08 9-3, i just ran into the same issues a couple of other had. I picked up used HU (12842427) and found that i'm unable to program it to a Bose system.
One post had two part numbers (12779270 or 12842428) that are believed to be compatible with the Bose system. These are getting hard to find and have been replaced by a newer part number (12849449).
Does anyone have a complete part number list of the HU's that will work with the Bose system?
In mean time, if anyone needs at non-base HU, drop me a PM.