Box and Filter only for 03-07 is
15860
http://volant.com/edetail.asp?ID=90
http://volant.com/product_intake.asp?TypeField=Hummer
Prob could find cheaper shopping around.
I ended up getting mine from Autoanything and added 15% off coupon with free shipping.
I really really like this set up. I am very happy using their box, and if you want more air flow, just pop off top cover or keep it on for a quieter CAI