H&R Sport Springs 2005+ Ford Mustang/GT/Shelby (V6/V8) - P/N: 51655 Product Model: HR-51655 Drop: 1.0 Front / 0.75 Rear H&R Sport Springs offer the handling characteristics and aggressive appearance that you’ve been looking for, without the harsh ride characteristics of less-advanced spring systems. H&R Sport Springs feature more control and are engineered for the street, making them comfortable and fun to drive. H&R Sport Springs are crafted from a special 54SiCr6 spring steel to ensure quality and performance.