It’s “Go Time” again. In the last year, rap’s stars have been at each other. The latest: Nelly vs. legend KRS-One, who said that Nelly’s party-boy image isn’t good for hip-hop. On Nelly’s upcoming album he says KRS needs a “rap pension and attention.” Last year Jermaine Dupri told a magazine he was a better producer than Dr. Dre. Dre responded by calling 5-foot-3 Dupri “Mini Me and a midget” on a rap. “I’m short,” Dupri tells NEWSWEEK. “But what is that to say?” Earlier this month Dupri shot back on the Web. He called Dre “gay” on a re-recording of a track Dre produced. Dupri also questioned if Dre produces the music he says he does. (Dre declined to comment.) A spat with Jay-Z has kept Nas’s career afloat. On Jay-Z’s album “The Blueprint,” he questioned Nas’s rapping skills and implied that he’d slept with the mother of Nas’s kid. Nas called Jay-Z “Gay-Z” on “Stillmatic,” his album that’s sold 1.5 million copies. (Nas didn’t comment.) “It’s a sport,” Jay-Z tells NEWSWEEK. Says P-Diddy: “I tell everybody, ‘Keep my motherf—ing name out [of] your motherf—ing mouth.’ Talking all that s–t about people leads to nothing but bad karma. And bad karma’s a bitch.”