Sonny's gift was alluded to in the movie when at the wedding reception Sonny's wife held her hands apart wider and wider with the women around her giggling.
Ti CL's comment, I really don't understand a few things that Puzo put in the story (prolapsed lady parts on someone in her young twenties did not belong) but Coppola did a masterful job of turning the story into a movie. If you read the book and was told how little of Lucs Brasi you would see in the movie, you never would have believed that he could come across as terrifying in the movie as he was in the book. Kudos to Puzo for doing more with less.