Good questions and also ones that I am pondering myself. Personal experience here in the ACT has shown that cone intakes seem to get the OK at rego inspections. I had bought a E36 M3 with a cold air intake and a cone filter. Went through without issues. The NSW guy who bought it off me had no end of troubles getting it registered until he fabricated a cover for it; passed no problems after that. Seems like open cone intakes are frowned upon in NSW. I should stress again, this has been my experience.
I have to agree with the comment that if you are concerned, then maybe mods like higher flow sealed intakes and oem style DVs are the 'safer' option.