I used the 3" aluminum flex tube from Lowes plumbing dept along with a 3" PVC drain that is made to fit inside 3" pipe
so this fitting is actually 3" OD. Remove the drains grille work so that the air flows better then you'll have a way to attach
the flex pipe to the air box.
Here is another update I modifield the plastic filler panel in the bumper so that the grille work where the tow hooks
go is opened up (lots of small holes were drilled). Then I put a 3"x4" PVC pipe adapter on the end of the 3" flex tube
and mounted it where the tow hooks would fit behind the bumper so that air now flows through the Black filler panel into the tube.
If you notice in the upper picture on the left side is where the flex tube sits behind the grille.
I tested it with my portable wind tunnel (leaf blower) to verify that additional air is going into the airbox (and it does).
I'm not sure of any gains but it's cooler air going into the airbox now.