I have since made a couple of calls to CARB, and Emissions labs trying to find out why a stock GT5-S is prohibited from being registered in CA. Basically, it is because you would have to pass the CA emissions requirements for the year of your car. While the Amerisport emissions stuff as new would pass Federal regs (possibly to CA standards also)it would be hard to replicate today. So the alternative seems in essence to be, complete engine and related systems replacement. You'd likely have to go to a EFI system and add cats and so forth.
The next part is the bombshell. The CARB guy says that any police officer, who chooses to and looks at your engine can write you a fix it ticket if he has a reasonable belief the engine is not stock. What is involved in such a ticket? Replace your engine and related componets to OEM standards, emission exempt or not. It seems overly harsh to me. Does anybody know if this is true?