Good to hear the supporting mods are in place.
I had my tuner make my Turbo intake pipe, I run a pod in a CAI box with a pipe running up from the front bar to pump cold air in while driving. ^^ Darren (Jet_r31) just made a recommendation for someone who makes them who may be local for you.
I run a HKS SSQ BoV and have no probs, Larger filter means more surface area to suck in air.
The fuel consumption should be the same with a proper tune as they are just capable of flowing more fuel, If set correctly that should only occur at High RPM / WOT.