So, spent the weekend doing a CAI for the 3.0d.
It was WAY more involved than I was hoping.
I was not aware the airbox was moulded as one piece with the tappet cover. The moulding if the airbox also housed the breather cavity. This meant that I had to cut the airbox off and seal up the breather cavity, then tap in a barb fitting to run a hose back to the intake.

I used a K&N Apollo enclosed pod filter. The MAF is also oval, which meant I had to make up an adapter. The pipe from the MAF to the turbo intake is now 3inch, and the way it has worked out has made it nice and easy for maintenance.

Unfortunately whilst making the MAF adapter I dropped the MAF and it is now faulty. I have unplugged it and it's ok to drive at the moment. New MAF for me!
Any tips where to buy them?

Anyways, it's not loud on the intake side, (almost which it was louder!) and looks quite nice. Enjoy.