Smog check is different than going to a state referee station.
If just a smog check, as long as your tune doesn’t defeat the DME from showing ready states, and visual smog defeat devices are in place you should be fine. Get a reader and check your ready states. In CA you’re only allowed up to 2 incomplete monitors.
Sniffer checkpoints are set up randomly along roads. As you drive thru, the sniffers will check for excess emissions. If you get flagged, it should be optional for you to have your car further inspected.
More info here
https://www.bar.ca.gov/Consumer/Road...n_Program.aspx