I have never seen or heard of someone upgrading the spindle on that kit because I believe it's designed around a stock LCA and Ball Joints. If you feel you "need" bigger wheel bearings and hubs than you are pushing that kit way way way way way way way harder than it was designed for AND you should look into doing a long travel kit with D35 4x4 hubs like with BTF fabrication makes or a Camburg long travel kit.