measure your battery before going to Autozone. Several different sizes are used in the Z4. I had to go back and get a different one because the first one was not wide enough.
They had two different size batteries listed.
2008 Space Gray Z4 3.0 si, Saddle Leather interior (to haul A$$)
2011 Nissan Frontier King Cab (to haul crap)
2010 Lexus RX350 (to haul people)
2009 Club Car Precedent (to putter around the beach)