I had around 6900 EMS (100%) at the end. Missed a small number of the sidequests.
re: guns overpowered. Hmm, I struggled in a number of the fights, especially in the
fight, near the missile trucks. How did people get rank X guns? Highest I saw seemed to be V. (my party for the final battles was me, ~55 Infiltrator w/Widow V & Phalanx V; Liara w/Arc Pistol & some ultralight SMG; Garrus w/either a Raptor or a Revenant & something else.)