I used them for a few years, then bought the monoleaf, to be truthfull there was an improvement over the car bouncing at launch, with ss springs, bounced every time, but did it the same every time and was consistent. With the mono,s car settld down, but the odd time, would get the bounce, but not as severe. I can only assume track conditions dictated a lot, car was still consistent, just the odd time ,and of course calvert tells ya not to use them, they are the seller taking your money, Tim