I swapped my two NZXT AER exhaust fans in my H500i with a Noctua NF-A12x15 120mm PWM (back) and a Noctua 140mm NF-A14 PWM (top). CPU is a few degrees cooler, but
Noctua Nh-D15 Chromax Black 140mm CPU Air Cooler | PC Studio
The Best 120mm/140mm Case Fan Shootout, feat. Arctic, BlackNoise, Noctua, and Scythe - YouTube