Yes, you will need to have a CARB number for the aftermarket air intake
installed on your Nissan Altima. The CARB number doesn't have to be stamped
on the intake manifold or stuck on to it as a sticker; all you need to do is
show the smog technician a copy of the owner's manual for the intake
manifold installed on your Nissan Altima. You should be able to download a
copy of the manual online from the manufacturer's website.
But again, to answer your question in short, your Nissan Altima will fail
the smog check inspection if you can not show a CARB number for the cold air
intake installed on it, or prove that the air intake is sold legally in
California.
