Hi Peter,
I have a pod filter behind the passanger headlight. For most of the journey from air flow sensor to throttle body I used some black ribbed ducting (rubber). Pretty sure I got it from purple pig. I think the inside diameter is around 90mm. I have used a section of aluminium tubing in the engine bay as I needed something solid to insert the air temp sensor into. I have had the aluminium section HPC coated to reduced heat soak (it runs about 8 cm above the headers).
http://www.purplepig.com.au/
Hope this helps
Regards
Cameron