As far as I am aware the V6 only has a small circular pipe straight into the airbox where as the 156 has a massive resonator box.
I have just put mine back in which I think is much easier than taking it out!!!
Keithyboy. Firstly remove the under tray if you still have it and the passenger side wheel arch liner.
Then: You will need to remove the snorkel type thing out of the resonator box first. Get under the car and on the front of the resonator box there is a philips screw. Undo that and remove the circular pipe by pushing upwards.
Then the hard part, the resonator box needs to detach from the air box, there are two push tabs on the top and the bottom of the connecting parts of the two boxes, push them in and pull apart. This was hard enough to do when the airbox and resonator box were connected outside the car let one in situ!!
Once detached you should be able to remove the resonator from the bottom, it is a tight squeeze though.
The airbox will then come out of the top of the engine bay.