Tesla, the Silicon Valley electric car start-up, is taking its sleek, $49,000 all-electric Model S sedan to New York City on a publicity tour. There will be a Model S on display in the Plaza Hotel this Thursday and Friday, and Elon Musk, the CEO of Tesla, will be on Letterman Wednesday night (and, apparently, he's bringing the car there, too!).I don't have a great sense of Tesla's exposure among the public at large. They've been in the news since around 2006, and Tesla's first model, the Roadster, is already on the streets, but I'd guess only about 10 to 20 percent of the country is aware of the company. A night on Letterman will certainly help. And the Model S is a car that, while still pretty expensive, has more potential buyers than the $98,000 Roadster.Via PSFK.UPDATE: Here's Elon Musk's appearance on Letterman.