I thought the Comptech Icebox was suppose to sound stock. I have looked everywhere for a solution, but it seems like there is a whistling sound coming from the actual box. I am a new to this forum so be gentle...

 

is it whistling? or is it slight hissing. It hisses... ever so slightly (vacuum) for mine.

 

The whistling noise is coming from the intake pipe. I know the icebox and it's basically like the stock box except with a conical foam filter and a small 90 attachment at the bottom. I got the same results with the stock airbox using a drop in K&N and removing the bottom attachments right up to and including the rubber seal. The whistling noise was accompanied with a low pitched hum. That hum was coming from the bottom of the airbox. It was basically vibrating. I replaced it with the AEM CAI (Not the V2 because there is no V2 for the Type S yet) and now all I hear is a slight sucking noise kinda like a vacuum cleaner when I accelerate. If you don't like that noise then put the stock box back in and just replace the stock filter with a high flowing unit. That will give you a bit more HP but it will sound as close to stock as possible. Just my 2 cents.