No real noticeable performance gain with a CAI according to my butt-meter, but there are some benefits. Your engine will breathe better with the extra air flow and measurable gains are possible if you combine a CAI with an ECU upgrade and the right free-flow exhaust system.

I must emphasize that the right combination of mods is critical. Otherwise, the gains you seek may not be realized and the wrong combination may just result in money wasted.