I bought the kit from them. It replaces the junk stock springs. They have a heavy spring or just a normal. I bought the heavy. I have the DFK cab without the doors added some weight. So went with heavy springs. As soon as I got them on I was somewhere around 10 and 3/4 of inch at bottom of receiver hitch. With original tires. Changed nothing but springs. Just put on a set of Maxxis Coranados. 26x11x12 in back and 26x9x12 in front. My ground clearance now is 1 foot from bottom of hitch. No lift anywhere.