Whether it’s performed for a sea of people, isolated to a radio station studio, or sequenced as the heartfelt centerpiece to their new LP, “The Last Goodbye” is an undeniable show-stopper among each Kills set I’ve seen. Celebrating an announcement of additional summer tour dates today, Alison Mosshart and Jamie Hince pulled this fine take on the forlorn gem from their short Blood Pressures unplugged film, which strips away the original’s piano/synthesizer-backed arrangement in favor of spare acoustic strumming and a lonely whistle solo by Hince.