O.K. finally got this install done, with some minor complications. First of all, I am no mechanic by any means but I managed to pull this off, with a little consultation from a couple people.
AFE package had all the necessary parts, and they look to be of high quality.
I first unpacked the box to confirm everything that was supposed to be there indeed was...Check
Then, I tried to "preassemble" certain things, like the rubber connector hose to each end of the air tube, and install the coupling onto the air box. This proved to be easy enough, except for the fact that the clamps supplied to connect the hoses to either end of the air tube were too small to allow for expansion over the air tube. I ended up having to get one size larger air O'Reilly Auto Parts for a little over $7. Problem solved.
Then as I popped to hood to follow the "easy" step by step instructions, complete with pictures, I notice a couple departures between what is pictured and what is under the hood of my 2007 Avalanche Z71 Flex Fuel 5.3L engine. Two primary differences, the pictorial does not show the two support arms that come off the back of the factory air tube and connect to a stud on the engine block (under the engine cover). After confirming with 4Wheel Parts, I see this as no big deal.
The other issue was that my factory air tube had a secondary reservior of some sort coming out toward the front of the truck, opposite to where the air tube connects to the throttle. This wasn't in any picture in the instructions, or any other factory engine pictures I could locate on the internet. After again consulting with 4 Wheel Parts (and TByrne - a big thanks), I came to the conclusion it was likely a resonator box or sound reducer or something similar, and unneccesary.
So today, I proceeded with the install.
Took all the factory parts off (fairly simple once you cut or disconnect the hose hanger from the factory air tube).
Everything else went in just fine, with only one minor exception. The AFE airbox bolts into three of the four factory mounting holes with the factory bolts. Trouble is/was, only two of the three holes lined up. Hence, I had to drill the third hole to match up with the bolt hole. No big deal, but I would think that it should have been correct to begin with.
Anyways, everything else went together as described. The two outermost screws that hold the AFE plate onto the airbox are a PITA as they don't allow for hardly any clearance. Since they were hex screws, I simply used an allen wrench to tighten them down.
Also, the breather hose coming off the middle of the AFE air tube connects into the engine via the factory connection.
I drove the truck around the block and believe I can notice a difference in the sound (although I must admit that I turned the radio off and rolled down the windows, which I do not normally do. I'll see how the throttle response and/or MPG is affected.
Next will be the Corsa sport exhaust that is supposed to come via UPS on Wednesday.