I use the 3400 lb SS springs I bought from Mancini. Yes the Cal Tracs are the best but I don't see me spending the $800 or more dollars for the setup. I don't think I would pick up any more then a tenth at best if I spent the $800 or more for the full Cal Trac setup. I like the SS springs on my street car and the SS springs are very consisdent on my car. Heck it ran 10.76 three passes in a row one day and that's on my 30 x 9 radial slicks. Cal Tracs are the best for sure if you want the most out of your car but myself I cant see spending $800 or more to pick up maybe a tenth on my street car. But if I was a full time racer I would definetly use the Cal Tracs. I also like how nice my car drives and rides on the street on the SS springs. Ron