Does it pop up a Check Engine Light? I have an OEM box with K&N drop in filter, but im out in NC. My K&N Typhoon intake system on there now doesn't have any issues with smog testing, see if you can pull up a CARB exempt number for that intake so it can pass.
2009 Cobalt LS XFE U74
Mods: K&N Typhoon Intake, Option Cat-Back Exhaust, Cosmo Short shifter, Maxxim Ahead 17X7's, MPx shorty antenna, FE5 Strut/shocks, Tein S Techs, Moog endlinks, Moog spring seaters, ZZP shorty header, LSJ downpipe, LNF front grille