I think your overestimating the benefits, I know people whIn fact logged their s4 cycle and seen practically nothing from it. It can be beneficial at moderate doses (10-30mg based on the research), but don't go overboard.
If anything, the higher you go, the more suppressive it will be to HPTA (please dont tell me that at high doses it isnt suppressive).
There are also plenty the night vision issues (for some driving at night was completely out of the question) AND I recall reading a 2011 study on Springer showing that it caused some liver damage in 20% of the subjects. So controlling the dose is still important.
As for endurance Mega, the evidence is pretty negligible for s4, but GW-501516 seems to be very promising in this regard