Hi mate. This is where I use products such as RTV 3145, wiping with alcohol first to clean the area. RTV is allot more expensive than standard silicon, but as mentioned before by me that it can bond an elephant to a battleship. I've used it for 20 years now and it is flexible but very strong, and high temp,
I discovered the stuff working in downhole drilling just up the road from you. I tend not to use my hot glue gun on plastic as it eventually tears loose if flexing to and forth.
These standard air boxes are a trade-off for fuel efficiency, power, etc, and if you let more unrestricted air through then you have to be prepared to let more fuel in also, as
maleko89 above. So it ends up the bike cannot be sold in some countries if the air/fuel inputs are too high, then the clever guys out in the street get a hold of the bike and increase the air and fuel intakes, and voila you have a beast in beasts clothing (upgraded VMax)