Many have. Definitely need on with aheat shield that separates the air available for induction from the hot under the hood air. Kn is not so good at that. Probably the best one around right now is the Lingenfelter CAI and they on sale till about Jan 17.
I will order one tomorrow and so far lots of people are doing so as well. To go along I also ordered the Corsa catback exhaust (On sale right this week on TByrne) to go hand in hand. Then I will be getting the Superchips tuner (available from GRAVANA) to optimize power and torque. Expect some significant hp gain by doing this. Superchips alone claims over 20 hp gain. I do not know what the combination of mods will bring me. If I can get 20 to 30 hp gain I will be satisfied.