Playing Nevada's Smog Game

I wouldn't necessarily bet on a bolt on cat doing the job. Having just taken a class about catalytic converters in my graduate studies they're really part of a full system, not so much a standalone piece. It would probably help some, but without full engine management I don't think it would work as well. If you were close to passing I could see one helping you make the grade, but to just bolt one on a car without tuning to match it I don't think it would get you real far with the crazy strict emissions levels they look for nowadays.