Got a modded air box ATM, Ran a piper x open cone designed for the astra 2.2 have a look in the inlet section. I think green filter also have one for the g 2.2, piper x open is pritty good as it comes with all the alloy pipe.
Car sounded great but bogged down power in the summer / in heavy traffic, i would have kept it but needed to free up a bit of cash so sold it.
You can create your own pipe as a few members on here have done or of you wait a bit a as good member on here who is handy (BURT) may be working on a custom idea for the Astra he is currently got items for the Vec.