The pulley the GTP guys are refering to is the Supercharger pulley. A smaller pulley will make the SC work faster thus causing more air to be forced into the intake. The Cold Air Intake (CAI) comes ito play by allowing the extra/more air to be let into the system.
You should still see a minor increase with a CIA on a GT. My guess is about 2-5 hp.
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S's? Oh it has SS's!!!