There's this guy on Edmunds forums named gagrice that is FOREVER complaining about "not being able to buy a diesel car" in CA because they do not meet CA clean air standards.

More, from World Auto View website:

"VW's TDI diesels pack a wallop of torque, scream down the highway and can run forever on a tank of fuel. They meet California's strict requirements for carbon dioxide and hydrocarbon emissions, but fail to meet the guidelines for nitrous oxide -- a precursor of smog -- and particulate, or soot, emissions. That could change. With low-sulfur diesel fuel like that already burning in European diesels, VW thinks it could meet California's air-quality rules, which are to be adopted by the federal Environmental Protection Agency in 2004. The sooner oil companies deliver low-sulfur fuels to the U.S. market, the better. "

More from a Car and Driver article:

"The trouble with diesels in the U.S. is at the tailpipe. They can't pass the emissions regs that go into effect in California this year and phase in across the country over the next four years. This may surprise those who've seen or sniffed the exhaust coming out of the latest passenger-car diesels—it looks and smells as clean as that of a gas engine to the naked eye or nose. The diesel combustion process, in which the air-fuel mixture is ignited not by a spark plug but by the high temperature and pressure created by a high compression ratio, is naturally clean in terms of carbon moNOXide, hydrocarbons, and other organic gases, so those standards are easily met. But those high temperatures and pressures result in oxides of nitrogen (NOX) and particulate matter—the soot your Olds diesel belched—that are very difficult to clean up, and the new standards apply equally to all fuels. No more special dispensation for diesel."

From a USA Today article:

"TDI models are not available in California, New York, Massachusetts, Maine or Vermont because those states have different anti-pollution standards. "

From another USA Today article:

"There's also the fact that modern diesels still can't pass the most stringent air standards — those enforced by California and four other states — because of their emissions of nitrogen oxides, or NOx, a key ingredient for smog. "

So there's your scoop............My guess is that you cannot get them registered with the MVD in CA.