Review on Spectre Performance Air Intake Kit: High Performance Upgrade, Engineered to Boost Horsepower: Compatible with 1999-2007 CHEVROLET/GMC/CADILLAC (Silverado, Avalanche, Suburban, Tahoe, Sierra, Yukon, Escalade) SPE-9900 by Leroy Wolfe

I immediately felt a small increase in power and acceleration on my 2006 GMC Sierra Z71, but after a few months I started to hear a knock in the engine. The filter was also clean. It initially looked and sounded great, but you realize how cheap it is. The air filter is translucent. Other reviews are correct, screws are cheap. The bolt/yoke holding the heat shield broke within the first month. Also, it kept slipping off the gas when I got into a dip or something, causing my engine to cut out. Overall just cheap. As a result, I reinstalled the stock air intake with a good air filter. The engine no longer knocks, the engine runs smoothly again. Next time I'll just go with K&N, you get what you pay for.