Here's my version of the air box mod. All supplies were purchased at Lowes...
Parts: About $20
(2) feet of swimming pool vacuum hose (1.5" ID) $3.07/ foot.
(1) 1.5" shop vac floor sweeper. $10
(1) radiator hose clamp to fit OD of hose. $1.50
(1) 1.5" PVC Trap adapter w/ nut. (PVC 104P 1.5) $3
RTV silicone sealant or suitable substitute (Household Goop, etc)
Tools:
Phillips screwdriver
10mm nut driver or socket & extension
knife
2" hole saw
drill
Hacksaw or sawzall w/ steel cutting blade or dremel if you like to suffer.
To start:
Loosen hose clamp between air box & intake plumbing. Unlatch & remove top of airbox. Be careful not to stress the wiring for the MAP sensor. Lay it to the side.
Loosen the (3) 10mm bolts holding the bottom half in & lift it out.
Drill the 2" hole for the PVC adapter 3" in from the side that's facing the radiator & 2" up from the bottom. Clean out the shavings. Try to land the starter hole on top of a vertical reinforcement. The ones on either side will hold the nut, while you turn the adapter to tighten it. You will have to trim what's left so the nut will fit.
Prep the PVC trap adapter by trimming off the "closed" end of the nut, making it a regular nut. I used my sawzall & metal cutting blade to do this. A hacksaw may have been safer. A dremel will work, but it'll be a hassle since the plastic will probably melt & make a mess. The walls of the box are not thick enough to allow the nut to tighten down, so the nut has to be trimmed...
If push comes to shove, you can just glue the threaded end into the hole & let it cure. I wanted the mechanical connection along with the adhesive sealing.
Reinstall the bottom half of the air box with the PVC adapter installed. Tighten the (3) 10mm bolts.
Next, move the A/C line that's passing through the 2"x2" hole to the left of the condenser over towards one side of the opening. This is required before the hose will pass through. Loosen the 10mm bolt that's clamping the A/C line in place & slide the line over, being careful to not stress it or allow metal to metal contact. Depending on the truck, you may have to move the line up/down/over. Mine had to move to the right.
Slit one end of the pool vac hose & trim out a notch to allow the clamp to squeeze tight. Slip the radiator clamp on, insert the floor vac adapter & tighten the clamp. Don't try to kill it, just get a snug slip fit. You can even glue this connection, if you want.
Wrangle the floor vac adapter behind the bumper & wedge it behind the lower grill. If you want, you can drill a small hole on either end & use a zip tie to hold it to the grill. Tension from the hose was good enough for me.
Run the other end of the hose through the 2"x2" opening & over towards the air box. Leave a little extra to bend around the A/C lines & to hold tension on the hose so it can be wedged into the adapter. I didn't glue this so the air box can be easily removed for cleaning or other service. The fit between the hose & adapter is fine, no further clamping or sealing needed. Trim as needed.
Drop in air filter, replace top of air box & tighten clamp between air box & intake plumbing.
Enjoy your 30 extra HP & 12 more miles to the gallon.