I switched from stock springs
in my forks, over to Progressive springs. About 10,000 miles later
the crap anti-dive blew my left fork seal. Found the Progressive
spring was broken when I was repairing the seal. I was rather bummed
that it broke and called Progressive. They said to ship them back
both springs and they would replace them, no receipt required and
no questions asked. That was cool of them, but I never really expected
a failure with one of their springs. It's not the first I've heard
of this happening with a Progressive.
I am in the process of installing
the Traxxion suspension now.