I will be running mine on the street almost exclusively. Why do you think there may be a problem with them? I don't think they would be prone to sagging prematurely. They look like high quality parts.
Mine only held the arch for about a year of street/strip action.They started out at stock plus one inch then they went flat after a while.I have heard they resolved some of these problems and when it does happen now you just send them back. Gus