My build thread with pictures
http://www.350z-uk.com/topic/62527-arrans-04-azure-350-gt-wheelsnuts-on-led-kit-more-121013/
And the nuts i have from demon tweeks, says they are steel
http://www.demon-tweeks.co.uk/performance/wheel-nuts-bolts/performance-wheels-coloured-tuner-style-wheel-nut