After a week marked by speculation about voter tampering, the audience for Fox's hit pop-wannabe series "American Idol: The Search For A Superstar" surprisingly booted Takoma Park, Md., native Tamyra Gray, 23, out of the competition Wednesday night. The contest is now down to three finalists: Kelly Clarkson, 20, Justin Guarini, 23, and 23-year-old Nikki McKibbin, who are all vying for the grand prize of a recording contract. Analysts are already predicting that the show's Sept. 4 finale will become the most-watched program of the summer. Steve Sternberg, senior vice president for the ad-buying firm Magna Global, tells the New York Daily News that he believes some 20 million viewers will tune in. However popular, the show (based on the British series "Pop Idol") has not been without controversy. Some critics have complained that one of the series' three judges, British music executive Simon Cowell, has been mean-spirited in his acerbic comments about contestants' performances. Then, earlier this week, the Associated Press reported that the show was being plagued by "power dialers" who were attempting to influence the final results by making more than 10,000 votes a night using Internet connections and high-speed dialing software. Representatives for the Fox show, however, have dismissed the influence of high-tech dialers — explaining that because they are voting for different singers, they are canceling each other's votes out.