Only one reasonably easy way to input a third party device into bose audio is via an fm emulator.
Most of these are shockingly bad mind you, unless you get one that can be hard wired into the fm aerial. But some loss of fm signal will result.
The Harmon Kardon drive and play works well. As it has an iPod cable connection, and an aux in via 3.5 mm jack. Plus iirc Davednd does an emulator via his shop.
It's still fiddly though, as the radio needs to be tuned to the emulators signal, on a frequency that is not occupied and static free. Rds and TP must be off to prevent radio retuning to a real station. This means traffic report alerts are na.
There are ways to input to the cd changer but this takes elevtrical knowledge I don't posses.
As said elsewhere though. There is a phone pre wiring loom on 2013 but that is mono only. So only suitabke for bt phone kits.
So hard wired emulator and Nokia ck 7w (?) bt car kit are way options.
Re hk drive and play there are. Options to add a bt receiver to the aux in that I have wip currently. Should work fine though provided the phone can distinguish differant bt connections for phone and audio, which iphone 5 can. This means iphone works with bt car kit for phone with mic etc, and separate audio for music and Tomtom voice (or whatever OTHER non phone related audio comes from the device, like tv or football for passengers)
Do able, but a patch into cdc would be better I guess?