I want to upgrade the air intake system to get more horsepower and fuel economy.

Haven't heard of anything specific to the Silverado. Here is a page of air filters but I am unaware of any that would drastically change engine performance. This is a good site: http://www.autoanything.com/air-filters/20A50341A1.aspx Or this one: http://www.knfilters.com/

K&N Air Filters makes several styles! A little pricy but gives you up to +26hp&23ft/lbs of torque instantly with the K&N intake and filterkit (cost about $350). They also make stock size/location filters(cost about $50) that flow more air cfm than oem stock filters! I personaly bought a hypertech power programer3 and the K&N stock size/location filter and went from average 14.9mpg to 19.7mpg! With the power programer(cost about $300) you can tune your trucks hp and ft/lbs up , change your top speed limiter up to 140 mph if your tires are speed rated for that, change shift points on your trans. , and very easy to install! go to stylinconcepts.com to check out their sale prices!

The air intake on these trucks is already pretty good. They pull cooler air already, as the air intake is routed as to not intake air that is being warmed from the radiator/condenser. So I wouldn't do anything at all to it basically :) Cheers

you really cant get better economy. if you get more airflow, then you need more fuel or the car will run lean. so a k&n (or whatever) air filter will make you get worse mileage.

the K&N intake is awsome. i have it on my 01 z71 and it makes a noticable horsepower and fuel economy change, not to mention a nice sound. only problem is that the filter gets dirty really fast and takes awile to clean.

No it actually dosen't give you worse fuel mileage. A cold air intake allows colder air into your engine and allows it to run at a better performance level. I've never seen a vehicle with an intake installed get worse fuel mileage. But don't just take my word google it or ask anyone whos installed one.

They are several intake systems you can buy. Volant, Airaid, K&N, AEM all make kits for the silverado. Cold air intakes will not lean out an EFI motor. The mass air flow sensor and computer monitor the amount of air and give the appropriate fuel, hence EFI. You will get a little better fuel economy and notice maybe a little power gain but dont expect the 26HP some advertise. For best results, combine the intake with a free flowing exhaust system.

I've got a K&N in my 01 Silverado. It clearly made a big HP gain. Fuel economy on it sucks anyway so I didnt notice a big change there, but still getting around 400 miles to a tank with 156,000 miles on it

another option is to look at changing your rear axle ratio - its like changing to a bigger rear gear on a bicycle - u will have alot more accel and torque and bit more rpms @ highway, shops can swap the gears for you, not sure what you have now but that might be another solution.. or a reprogram? K&N filters can actually let sand thru as they have too large holes - this has been WIDELY proven, a good non-paper (cotton) filter will do better at keeping your motor clean imo -

I got the Spectra 9918 for my 2011 Silverado 5.3, and I LOVE IT!