I am very familiar with this mod as I had one on my car. It can be very effective and I have seen dynos showing as much as 23 hp from one. BUT, they work by leaning the car out, which is not good. If you buy one, you really should consider a dyno tune to prevent the lean condition from being too much. Also, if you plan on adding a power adder later like a blower or nitrous, don't waste your time with it at all.
I sold mine and went with a Steeda CAI due to problems with the lean condition from the C&L.