“Twilight’s” Robert Pattinson and Taylor Lautner have a friendly competition going on as the make the rounds promoting the upcoming “Twilight Saga: Eclipse.” But the rivalry also extends to the entire Cullen and Wolfpack clans. In the latest in their game of oneupmanship, the shape-shifting werewolves say they worked a lot harder on-set than the vampire actors. The actors say they all needed to get in shape to match descriptions of their characters in Stephenie Meyer’s books.