“Star Vehicle” follows the downward spiral of movie driver Donald Cardini, a self-professed movie buff with a penchant for explosive violence when provoked. Driving the stars of low-budget movies, along with their fragile egos, to and from locations in the middle of nowhere, pushes Don’s buttons in all of the wrong directions. When Luke, the young and self-absorbed writer/director challenges Don’s authority, murder and mayhem ensues.