Tanabe TGF107 GF210 Lowering Spring with Lowering Height 1.0/0.5 for 2005-2006 Subaru Impreza WRX/STI 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