I had mine re-arched every year by the local spring shop for $12.00.
At least on Pacers they need it to keep the tailwheel from shimmying.
Even the brand new ones from univair need a little more arch.
New vs re-arched, made no differance.
My Dad had a local spring shop re-arch his and hasn't had to redo it. He did put a little more arch in it. I found a letter once from Univair admitting their Pacer springs didn't have enough arch but they didn't want to change it do to paperwork.