Suspension upgrades are not model-specific. If you use the search function for "suspension upgrade," you'll find quite a few hits. If you put on heavier springs, you won't necessarily gain height - and may cause more issues. When upgrading suspension, you need to consider shackles, hangers (and reinforcement), wet bolts, and the equalizer system in addition to the springs. These are all known weak points and springing a unit more stiffly will cause premature failure of the other components. The best way to lift a trailer is with lift blocks between the springs and axles. You may want to research in that direction (as well as looking into the other upgrades). The search function on the forum is your friend.
Rob