Hey mate,
That noise is difficult to diagnose, theres a bunch of "could be"s, best bet to DIY would be to get someone else to take off slowly in your car while you're down on the ground beside it, to see if you can figure out where the noise is coming from. Probably needs to be taken somewhere though, to places that deal with that stuff daily, they might diagnose and give you a quote to fix, then DIY if its easy.
Id say factory airbox with a cold air intake is the go. Have a look at this ebay link
http://cgi.ebay.com.au/VN-VS-V6-COLD-AIR-INTAKE-GENUINE-HOLDEN-COMMODORE_W0QQitemZ190209033010QQihZ009QQcategoryZ36680QQssPageNameZWDVWQQrdZ1QQcmdZViewItemPods aren't very good when your engine bay gets hot, and police don't really like them either. The factory cold air intake would be more discreet, and be better for city driving.
Cheers,