I thought Metallica's performance of "Moth Into Flame" with Lady Gaga at the Grammy's was outstanding. Sirius XM Octane just posted a link with James' vocals put back into the recording, and man, good stuff. I knew LG would do a good job -- she's a metal fan. Loves Maiden, Metallica, etc. Her voice has the right edge for metal, and the range she has, particularly at the end of the song, really shined. Good stuff.
As for the tour, Volbeat and Metallica -- saw that on the Death Magnetic tour. Really good. So far, no date by me yet (which is weird, since, Bay Area), but it'll happen.