It's always interesting when you go back and reread the rules you thought you knew. I think Tom is right. The only emission controls that are listed for removal are air pumps, EGR (and associated lines) and the catalytic convertor. Maybe Kirk's fuel cell rationale could be applied, but that seems a stretch.

And I don't think there is any general language allowing emission control removal, since the amount of such removals that are allowed vary by category.

Where's the smiley for letting sleeping dogs lie?