There are a few things going on here. First, the red bushing for the spring is polyurethane. That's no big deal and it's really easy to do. I'm not sure you get anything from the use of polyurethane in this application but it's cheap and easy to do. The long bolt you see is a lot more important. The bolt is much longer than the stock bolt and it allows you to lower the rear of the Corvette. The third thing is the camber control rod from Vette Brakes. The real beauty of this system is that you can easily change the rear camber. The left decal you see on the rod means that it's a left hand thread.