Not exactly sure what you mean by the HSV airbox- I'm assuming you are talking about the $50 CAI from Holden? I used to have one before the Starr box- definately worth it and should be available from any Holden dealer spare parts section or Rare Spares.
Research is starting to suggest that the theory of an open pod losing power due to breathing hot air off the exhaust may not be noticable in a low power application anyway so you could get away with using a pod but obviously not the prefered option... The cops can frown upon them aswell I think.