The videos and other peoples instructions are better than the included ones... But one part that's correct is to bend that bracket a small amount at the last 1.25 inch... Almost at the very bottom. Once I did this it snugged up perfectly flush to the car when I tightened it.
The stock instructions should include CanadianGuy's regimen of Loctite on the nuts and screws.
The rears stay tight on their own in my opinion but they do something I don't like... The rear bumper has no support in the area attached so the flaps have a tendency of sitting crooked after a couple days due to the torque of the screws on the rear bumper. If you look at pictures on most people's car you can notice this in the rear. Perhaps I'll loosen the rears to relieve the stress and re tighten them so they sit completely level again.
To be clear, they don't fall down, the torque of the fasteners seems to curl them upward so they cant upward toward the middle of the car if that makes sense.