I have not tried other springs. I feel like the back of the sled has often returned up ok. The front shock collapses more and more as a day goes on. the limiter straps end up with a lot of slack even when there is no weight on the sled. Then it feels like small bumps can bottom the front track out.did you try higher rated springs? i replaced the rear torsions on my 11 a few years ago when they sacked out from milage/age.