This kit gives a substantial improvement in ride quality while improving handling as well at G-out resistance. We've found the perfect combination of spring length to rate ratio and are very happy with our results. This kit is for all four corners of the machine. After a lot of testing, it was determined there is no need for a dual-rate spring setup on the front of a RZR 570 50". We decided to stay with the proven single rate spring setup we've been using for years on the fronts of the narrower RZR's. The rear however has found large improvements by switching to a dual-rate combination. You can expect a more stable ride with improved comfort and handling as well as substantially reduced rear "bucking" with this kit.