“South Park” creators Trey Parker and Matt Stone have formed their own production studio, Important Studios, with $60 million from boutique investment bank Raine Group, the Hollywood Reporter and New York Times report. With an estimated value of $300 million built on revenue from Comedy Central’s “South Park” and the Broadway hit “The Book of Mormon,” the studio will have the power and money to approve television, movie and theater projects, including a big-screen version of “Mormon.”