Someone suggested a heat gun to make the rubber easier to form. Not sure if it works. I could not find my heat gun and yes it was a total pain to get that sucker to stay seated. Problem seemed to be more the metal reinforcing than the rubber. Ended up using some electrical tape to hold the ends in place but it still was not easy. In any event, it's on but it still does not seal very well against the car. Bottom bows out a bit and sucks some air from the engine compartment.
Question for you guys. Do you keep the rubber plug on (sealed) or did you remove it and let in air from the engine compartment? Since the inlet wasn't properly sealed anyway, I took the plug off. Engine growls more when accelerating and I try to believe I have more power and better gas mileage. Please don't burst my bubble.