if your leaking,,new o rings,,weight of oil depends on the size of the car and what your doing with it,,i think your car ,,you should go 5o wt all around for having fun,,,new boots only helps the sand or dirt from getting in....check your cars website,,i believe you have an 1/8 scale right??? any shock oil will do losi,assc,or trinity,,your spring rate, if you want to go stiffer put some spacers in......