Tanabe TNF063 NF210 Lowering Spring with Lowering Height 1.2/1.2 for 2003-2007 Nissan 350Z Z33 All coil springs feature Sustec 210 technology which is a series of manufacturing methods developed to create a stronger, thinner, and lighter spring using high tensile steel Tanabe springs are some of the strongest springs available for automotive use (2100n/m) Tanabe springs carry a comprehensive 3 year warranty and are designed to not sag