PUMPED UP: Stephen Sadove, chairman and chief executive officer of Saks Fifth Avenue, bought himself a shiny new set of wheels at the Westchester Mall for Christmas. He’s the proud owner of a Tesla Model S electric car, in which he was spotted tooling around in Westchester over the weekend. Powered by electricity, the car drives like a sportscar and features a touchscreen, which accesses music, maps and the Web (he can check e-mails), as well as a 5.3 cubic foot compartment under the hood, and a roomy rear hatch, for storage. Freed up from buying gasoline — at least for this car — all he has to do is plug it in at night to refuel. Sadove gave a quick tour of his new car, which is not only stylish, high-tech and energy efficient, but an amazingly quiet ride, he said.