I've had good luck with re-arched springs on my 'bolt and on other trucks. I had a 1-ton dually that I took to a shop and they re-arched the rears to stock height, after that I pulled a very heavy (2000 lbs on the pin) 5th wheel that we took all over the USA as we full-time RV'd for 3 years. The springs remained at the stock height.
All the experience I've had with de-arching or re-arching has been with the spring worked cold. No heat treating necessary.
Would the new Eaton springs outlast the re-arched ones? Maybe, but I'd hate to have to put money on it.
THIS shows one method if you want to do it yourself. The pro shops I took my springs to all used the "2 bricks and a sledge" method. Either one will work.
