I have a couple of those spark-plug-something thingies in my gf's Accord. It was getting a p0420 code for cat ineffeciency on and off for some time before I installed those. But the car was able to pass smog two years ago while the CEL was temporary off, so I think the cat might be ok

Do you guys think it's possible to pass the smog and visual with that mechanical fix? Do they check any readings from that rear sensor? Or is it pretty much exhaust gas evaluation and than visual inspection?

Thanks!