i've been running them for the last month and they have yet to start leaking! they do feel harder than the stock o-rings and have some "sticktion" when you build the shocks, but i can't tell the difference when the shocks are mounted on the car or on the track.

i've also tried a 50A durometer buna-n o-ring, and those feel just like the stock silicone o-rings, but started leaking after about 5 runs. i've got about 20 runs on the quad rings so far with no leaks

btw, this is in the v1 shocks. i plan to also put them in the v2 shocks though.