Review on K&N Cold Air Intake Kit for Hummer H2 6.0/6.2L V8: Increased Horsepower Guaranteed + 50-State Legal (2003-2009, Model: 57-3037) by Charles Palma

I bought this and a Borla Cat back exhaust for my Hummer H2. I installed the air intake first and then went for a test ride as I wanted to test performance and sound separately rather than doing everything at once. After installing the air intake, you could definitely notice a little more power, as if the engine was just sucking air faster (which was the goal). On test runs with air intake and exhaust, I see about a 1mpg improvement when cruising on the freeway, but almost no improvement when towing a small 1,000-pound trailer on it. So, this did what I was looking for but at a price. When I went for a test ride after installing the air intake, I immediately noticed that with more than the slightest touch of the accelerator pedal, you had a nose that you never had with a standard air intake. The sound sounds like you put some metal bearings in a can and then spin the can by spinning the balls in the can. It's not a noisy dinner party, but there's enough of it to annoy. I can pull out the air intake to eliminate the noise.