Thats right, the simple rule is that any modification that changes the consistancy of the gas from the exhaust is a no go unless it's EPA'd and cleared. So change AFR and things like that (with a new bigger turbo as if this wouldn't be done) are all no go's.....so they say
On the BOV side of things the reason they recirculate the gas (not air) is to burn off excess vapours etc, if these are vented to atmosphere then thats another EPA no no, it's not the noise that they are worries about.
I'll track down my last dyno sheet and scan it in, would be good to compare the power curve's etc since we have such similar mods and the same power output.