JBA makes shorty headsers that bolt right up and star CARB approved. Headers will need mid pips with or without cats. JBA also sells them. I love their products and have JBA mids(catless) and catback on mine. Just waiting on headers until I have cash to waste.
It is almost pointless to mod a car in CA. It just too much a PITA wit hall their regulations.
2003 Corvette Z06 - MGW shifter, Corsa X pipe, Corsa Xtreme exhaust, PowerStop rotors/pads, Conti DWS tires, C6Z51 F&R sways, Depo C5R headlights(not installed yet)
04 GTO - sold