Susan Powter and her high-intensity “Stop the Insanity” infomercial were big winners Wednesday at the National Infomercial Marketing Assn. Awards in Las Vegas.Powter, she of the blond buzz-cut hair and in-your-face presentation, took honors for female presenter; “Stop the Insanity,” by Real to Reel Prods. and Steve Ober and marketed by USA Direct, was awarded infomercial of the year best production. Bodybuilder Jake Steinfeld won the male presenter award for his “Firmflex.”"Hidden Keys to Loving Relationships,” hosted by John Tesh, won for best talkshow infomercial. “Personal Power 4″ took best documercial honors for Lieberman Prods./Guthy-Renker Corp. direct marketers, as well as an award to Lenny Lieberman for best writing and Lieberman and Mick Diener for directing. Awards are selected by infomercial producers, cable nets, media buyers, product manufacturers and marketing companies. The National Infomercial Marketing Assn. is based in Washington, D.C.