If we allow the catalytic substrate material to get hot enough, prior to inspection, our cars ought to pass the sniffer test no problem. People have suggested using header wrap on pretty much everything located upstream from the cat. Well, maybe not the up-pipe. Just make sure that you drive the piss out of your car before pulling into the test station & get that cat nice & hot. I know for a fact that a N/A contour with headers and NO main cat WILL pass the sniffer test. As such, I have no doubts that a boosted 3L WITH, a functioning main cat, will pass as well.
Personally, I'm more worried about the visual. I'll still have a main cat, but hopefully I'll get a REAL MORON to check the engine bay.
"Hey, what's that turbo looking thing over here?"
"That? Oh, that's just an extra A/C compressor- you know how hot it gets here..." - (while you discreetly slip him a twenty).