We had to replace springs also, our 2008 Bighorn 3600RL, after much research and help from all the guys on this Heartland site, I decided to replace my springs with the same weight rating as the old ones. My old springs were so bad they were shaped in a "W" shape, I purchased new springs, American made with the same weight rating and it rides like it should. It doesn't bounce around as much and doesn't sway side to side. I didn't want to go to a higher weight rating because it will make the unit ride harder and bounce things around more, a stiffer ride. I don't have the name of the supplier I used, but any american made leaf springs will probably work, the chinese springs seem to be softer even thou they are rated the same? Good luck.