Help! Should I keep the exhaust fan?

I bought my friends' old PC and I want to change out his old AIO to a Peerless Assassin 120 SE and I don't know if I should keep the exhaust fan behind the CPU cooler. It's gonna have 2 fans attached (one in-front and one in-between the heatsink) so the exhaust fan will have space. I have 2 intake fans in the front also, and the PSU has an exhaust on the bottom. Case: Zalman Z1. Cpu: 7700k GPU: EVGA 1080 FTW2 Pictures: https://imgur.com/a/0QUjYoY