What can i say the install on my '03 Avalanche was easy!! It took me just a little over an hour to install. After taking out the stock air intake you could see why the air flow is so restricted, there were only 2 little holes punched in the inner fender well for the stock intake to suck air through. You can definitely hear the sound of air rushing in to this intake when you get into it. Kind of like the 4 barrel kick in sound. I just installed it so I have not seen what if any mileage improvements it may make. I also have a dual exhaust cat. back system installed and it seemed to have a little deeper sound to it. I would buy this unit again.