I had a couple of dents in my airbox when I got my bike, decided to try to fix them myself. I used my dremel tool to grind through the outer shell.
Note: Be careful here there is less than a ¼ inch space between the two shells.
I made my hole about an inch in diameter so I would have plenty of room to work the dent. Aluminum unlike steel does not have memory so many of the techniques use to repair sheet metal just won’t work on Aluminum, another point to keep in mind that aluminum will loose its tensile strength if to much heat is applied also you can ruin the job by stretching the aluminum, or bringing it to the point where the metal will start cracking from work hardening. I reworked mine slowly and was able to bring it back to about 95% of its shape. Needless to say my next mod will be a carbon fiber airbox cover.
Good luck