I posed the same questions to the folks at Tekno RC after experiencing the same pivot ball problem. Their advice was to stick with the stockers as the RPMs are prone to the same problem. You can upgrade to the
RD Racing aluminum carriers but they are quite pricey.
They also suggested to check for slop by making sure that the pivot ball caps are tightened correctly. I also put just a small dab of Shoe Goo on the caps before screwing them in to ensure they do not back out. And finally you may want to remove the rubber dust covers that fit over the pivot balls. There is a possibility they will bind when the suspension is at maximum travel and actually help in the process of popping the balls out of the socket.