yea, same here... i had problems with the old alloy ones all the time, then went to the setscrew/nut combo. on my 416, i did assemble it with the newer hex style ones that came in the kit, crossed fingers, and ran it last saturday... took a few fairly hard whacks, but the only thing i had problems with was that both of the ones in the center steering mount worked loose.. twice.
im heading to a big race around new years, at a track that has pretty stout boards, so for sanity's sake, i swapped all the critical ones out back to the steel/alloy combo. now the only thing i worry about are the turnbuckles.
back on topic, the car drove like a dream, tho...very stable, yet turns in great... this is on what i would call medium bite carpet, rubber tire. ran the kit setup, with minor adjustments to the droop.
what would most people change to get just a tick more off power steering? mainly at speed... i feel its a bit tight coming off the sweepers, but rotates great on the lower speed stuff...