a) Mars > Bruno Mars.  Mars probably aren't available, however. 
b) GWAR has sucked for decades
c) this is a NEW YORK / NEW JERSEY Super Bowl.  It doesn't get more New York than Chain Gang. And on the Jersey tip, unlike Bruno Mars or GWAR, Chain Gang actually have a song that directly addresses where the game is being played (ie. "Death At The Meadowlands"). 
d) NJ Gov. Chris Christie is a big, big fan.  
e) have I mentioned yet that GWAR sucks?