I wanted to do some chopping on my stock airbox after seeing it in another thread. Here'* what I did. Tools needed- dremel with cut-off disks and a thin hand saw (jigsaw blade in a vise grip worked great for the plastic ribs that the dremel can't reach).
Here are some before pics of one half
The other half
After of the first half
She sounds a bit better, with more of a 'woosh' when gunning it. However, this sound isn't quite as pronounced as those I've heard with cold air intakes and probably FWI (as I've never heard one). Not bad for a half hour and $0.