Also, hot air is the enemy of power, but I challenge anyone to hold their hand on their "cold" air intake after their next drive home from work. CAI's would work much better if they weren't made from aluminum.
Actually.. funny you mention that.. I did hold my hand on the upper section (the section which connects to the turbo inlet) of my CAI on weekend after a 30-40min drive in hot weather (to test out the new TIP I installed) and it wasn't scalding hot, it was pretty warm and the lower part of the CAI was actually cool to the touch.

However on hot days, like yesterday, with stand still/stop and go traffic it was very hot all the way down to the lower section of the CAI.. so I guess it depends on what your driving conditions are like..