a little bit of photoshopping...
its a bumper for a 180sx http://cgi.ebay.com/ebaymotors/HiFlex-171b-Body-Kit-F-Bumper-Nissan-240SX-89-94-180SX_W0QQcmdZViewItemQQcategoryZ36475QQihZ010QQitemZ200157572042 but maybe you can make it fit for the 280zx. at a quick glance, i kinda looks like a porche