what about the airbox out of a 08-14 wrx or 08-19 STi?
for reference, here's an STi one:
https://www.ebay.com/itm/2008-2019-S...sAAOSwBw5dr7Zr
I might have my 08 wrx's air box floating around. i'll check my garage. I DO have a 08-14 AVO turbo inlet as well... could never get the bastard successfully installed on my old car. not sure how much piping you have figured out yet.