Are these sincere attempts to ease global warming or merely cynical bids to capture the PR lightning of the all-electric, 0-to-60-in-four-seconds Tesla Roadster? George Peterson, the president of industry analyst firm AutoPacific, says that major luxury manufacturers are developing high-performance green tech with a wary eye toward future regulation of carbon-dioxide emissions. Not to mention meeting the proposed 31.6mpg U.S. standard by 2015. But many companies, he believes, are merely trying to attract image-conscious investors and buyers. "They'll sell so few cars that the environmental impact is almost nil," he predicts. "It's mostly about bragging rights."