The 1957 Broadway hit West Side Story is an icon of musical theater. It sets Romeo and Juliet on the streets of NYC, where the rivalry between two teenage gangs — Puerto Rican and white — dooms the love between Maria and Tony. When it first opened, its gritty theme of urban gang violence set a new tone for the musical stage. The show has, on occasion, aroused controversy over perceived racial stereotyping. Now, a PACE production at the Academy of Music in Northampton seeks to bring this 50-year-old masterpiece, and its explosive themes, up to date.