Buying a car “as-is” does not apply when it comes to smog checks – by law, a car that is not able to pass smog can not be sold.
Why is that important? Starting March of 2015 new California rules state that a car that has a miss-matched catalystic converter can not pass smog (even if the said converter is working just fine, and the same car with the same converter has passed smog successfully in the past).
So, if you are buying a car that has not had to pass smog check since March of 2015 – make sure to have to check if the converter installed in it is original. Otherwise, chances are high that you will not be able to pass the smog check the next time around.