Yup, they are correct. I don't know of any aftermarket Subuar parts that are CARB approved, accept maybe a gen 1 or 2 borla header.
When you take your ride to get smogged in a few years, at least keep the stock intake. When they look (if they can see) the header just tell em' "oh the heat shielding has fallen off after years of auto x"
CARB doesn't necessarily mean it robs you of power. You can get a new corvette, and for $20,000, Reeves Callaway will slap on a twin turbo,rebuilt engine, AND have it CARB certified. Although $10,000 goes to CARB. It is just expensive for manufacturers to get their stuff CARB certified. I'm sure the Ganz flow, or Cobb's CAI has little effect on emissions...but is it carb certified, nope!
EDIT: Since you're from "The Birthplace of the Republican Party" you don't need to worry about CARB.