Sport Lowering Spring Kit – 2002-2005 Thunderbird. Want improved appearance and performance for your 2002-2005 Thunderbird? Looking for replacement coil springs but can’t find them? Here’s an affordable solution! Our Sport Spring Kit offers the handling characteristics and aggressive appearance you’ve been looking for, without the harsh ride of inferior spring systems. Crafted from a special 54SiCr6 spring steel, with a strength rating of 290,000 psi, these superior quality springs provide unrivaled tensile strength and resiliency. Our springs are engineered for street us making them both comfortable and fun, and lower the stance of your Thunderbird by 1.3″ in the front and 1.0″ in the rear. Precision made in Germany. Set of four. Fits all 2002-2005 Thunderbirds. In stock for immediate shipment!