Is there a difference between 422 California Emissions and 423 California Emissions not required?

My dealer tells me that I cannot order 423 in MI, and that I must order 422. I don't like hearing "California" in anything I buy, because everything is banned or illegal in California or that CA emissions tacks on 50 lb of emissions junk that still does not satisfy the CA legislators.

I see that the 05-up GTs only have 2 cats anyhow, but I was wondering if there was any difference between the two emissions packages (extra parts, less horsepower, etc...)