I haven't used S4 and won't ever plan to but I know ph's gave strength gains like that. My questions to you is gains in strength like what?
I just started LGD but I primed my body by having a strict diet, core lifts pushed to the max and support supplements all before starting LGD. The reason for this is if my lifts go up any it's because of the LGD and not just because I am putting in more effort or placebo effect.