I have the comptech icebox. To an untrained ear it sounds stock until 6000+ rpm but for someone who has driven the car stock for 20,000 miles (me) overall the car has a much deeper growl.

You only need to buy the icebox and foam filter to have a functioning comptech CAI. The polished short-ram is just for show. If you don't plan to run a bypass valve then go ahead and get the cheaper AEM CAI. If hydrolock is an issue where you live I would recommend going with the icebox. The bypass valve reduces the power gains on the AEM.

Or you can make your own custom icebox for under 50 bucks, as many people on this board have done. (Search for DIY CAI)

Shingo