I put some clear silicone over the hole it'll be fine till it's not I guess.
Be sure when you trim out the piece inside the air box that you end up with a flat flush surface. The defender and the face of the air box need to be mated. The less silicone the better.
I used a multi tool, a saws all, a cutoff wheel, a knife, a sanding disk, and a deburring tool. I made a real mess of it
Drill the holes with a super long bit. When I messed up on that first hole it ended up way too close to the inner edge so I had to grind a flat spot on the screw head so it would fit up against the wall.
Warm up those reflector stickers with a hair drier or they won't come off.
Layout your intake side vents measure three times unlike me. I measured in 5/8 but after I drilled the holes realized it needed to be 7/8 now that's goofy too.
Oops