I thought I would share some knowledge that Gilbertd and I have accumulated over the last few days.
This is only relevant if you want to keep the original radio. The alternative is to install a new headunit with the relevant connections.
**Notes - Parrot have stopped making handsfree kits due to most cars having them inbuilt. Stock is difficult to come across so I would suggest buying this kit ASAP if you intend on install handsfree into your P38.
Each speaker in the KH / Alphine system is amped whereas the standard wiring harness and amp box assumes that the speakers need amping and therefore the blue box provides 20w per channel. The result is a very loud huming/ buzzing when switched to the phone mode.
To prevent this you need a separate harness from justcarkits.co.uk
It says out of stock but when I called him up, he had some in stock.
The blue box fitts down the back of the radio. As does the excess wiring.
The microphone fits nicely onto the plastic roof light and the wiring can be hidden in the roof lining
The usb and line in socket fits well into the glove box
The screen fits well on the right hand side of the middle vent, left of the dash board
I am due to receive my new wiring harness and will post an update asap.