gvr4ever I personally wouldn't waste my money on cold air intakes. They seem to be nothing less than a scam like the electric supercharger, or those stupid "vortex" air spinning things which claim "20% more HP and 33% better MPG!". So by installing an air spinning, my fuel efficiency is going to go up to 50 mpg??? Pardon me, but that's bullsh*t. People who actually believe these non-sense claims are idiots. If these cheap products really worked, don't you think auto manufacturers would have used them?Not all CIA systems are BS. Many are, and most of them are not worth the money, but on some cars, they can be a big difference. I personally like K&N products, but I wouldn't pay for a CAI unless it was a car that could really take advantage of it like a turbo car, or a big engine.I would imagine that auto makers don't use them because cotton reusable filters cost more then disposable paper filters.If I plan on keeping any time long term, I at least get a K&N drop in, or in our corolla's case, a TRD drop in. Paper filters for imports are not the cheapest, and while the original cost for a reusable cotton filter cost more, the cleaner kits (that last multiple cleans) are only $10 each, so in the long run, they might even save money over the life of the car.