Here's a link(1st) on the FSC.com site to the CAI(Cold Air Intake) search. That will discuss the basic CAI that are out there. Along w/ what some of the gang over there think of the different CAI available for our trucks.
But, I, personally, like the AEM Synthetic Dryflow Brute Force Air Intakes or the SLP Performance Parts Cold Air Induction Systems.
Good luck!