I've done 4:08,4 with Mahjarrat, Berserk and Equilibrium aura so far. So i believe you can push sub 4 with each of those. Still trying to figure out when to save primordial shards, when to use them and whether i want to zgs or zerk pad 5. In some of my kills so far, i get there so fast i'm not getting my zerk off cooldown so I'm forced to use zgs. I guess i just gotta figure if i can boost my zgs dps enough by saving roar & primordial shards for that specific moment. Anyway i feel like i'm getting the sub 4 in near future. Also the casual kills are absolutely insane now, getting like consistent 4:15~ or under