These are what I am talking about:
However, they may have changed the spec. which I am not aware of.
Tein S.Tech Lowering Springs TEIN S.Tech Springs are an excellent step towards suspension tuning.They offer an aggressive appearance and increased road holding capability. Designed to be used with OEM or OEM replacement shocks.Each application is road tested in the UK for the proper balance between performance and comfort. Comes with a 1 year limited warranty,Manufacture : NissanModel : 350zEngine : 3.5Year : 2002-2008Chassis : Z33Front Lowering Appox : 17mmRear Lowering Appox : 14mmNotes : Excludes Cabriolet Additional Features:Chrome Vanadium SAE9254V ConstructionProgressive Spring Rate DesignIncludes Silencer Rubber on certain applicationsGreen Powder Coat Finish