I talked to a representative from Audi who told me that the TT engine specs hadn't changed from 2005 to 2006, but because of stricter emissions standards in California, Audi couldn't offer the car for sale in that state or in the other states that have adopted California's emissions standards. I looked up the TT on the EPA Web site, which has a database of cars and their pollution levels, and the TT doesn't do so well on the EPA's Air Pollution Score, getting a 2 out of a possible 10. I looked at the Mini Cooper S by comparison, and it also gets a 2 out of 10 on the scale. The EPA site lists a separate version of the Cooper S for sale in California and the other states that follow its emissions standards than the one for sale in the rest of the country, so it seems that Audi chose not to engineer a TT version to meet California's standard. That may not be the best move on Audi's part because California is probably a pretty big market for the TT.