The airbox is not ABS.
Here's a previous thread summarizing adhesives used for other airbox repairs:
http://forums.pelicanparts.com/porsche-911-technical-forum/853053-air-box-repair-myth-reality.html
My recommendation: Use Loctite "Plastic Welder" two-part epoxy. Clean all surfaces very well and lightly abrade them (scuff them up) prior to application of the adhesive.