A CAI will help Low-midrange power and torque, due to the longer path that the air must take, and longer-runners and a long intake tract equal more efficient operation at low-midrange rpms. Not to mention the benefit of the slightly cooler air...
BUT I will tell you from experience it's not worth the extra 2hp or so for a CAI becuase if it's flooded it will damage your engine...
I live in PA and I had a CAI on for like 5yrs, Just ONE TIME it rained too hard and I ended up in a puddle by accident, cause I was ALWAYS on the lookout, and I ended up with a completely ruined engine, It bent the #1 cylinder connecting rod like a banana...
We had to tear apart the WHOLE engine and re-hone the cylinders and everthing...The whole intake mani was flooded with leaves and sticks also...
Anyway, she's been running strong now for 2+ years.
Get the short ram, or worry everytime it rains,
Later,
Mike