Everyone is going to swear by whatever CAI they have installed. I went with the C&L street intake with the Xcal2 custom from Brenspeed....I gained nearly 30hp at the wheels.
Demolet, and X cal 2, both for right at $500 (that was custom painted 07 torch red), unless you have the big bucks for the WMS. I gained 28 hp/20lbswith the 93 tune. Demolet dot com, check it out!