You can get those "burger" badges from Tarmac Sportz a trader on here.
Link: http://www.tarmacsportz.co.uk/GB/350Z_NISSAN__02-08__JDM_BLACK_Z_LOGO_EMBLEM/350ZJDMLOGOBLACK_.aspx
Also lot's of other style Zed badges available from Asad here: http://www.350z-uk.com/forum/212-350z-370z-z-emblems-accessories-sales/
Thanks for the links :-D