get some weatherstripping off amazon or something, then coat the area around your gpu fan and your cpu fan so you have a ring of stripping in the gap between your gpu intake and the case itself. this will reduce noise by reducing the amount of turbulent air around the intakes and prevent re-circulating which will also reduce temps a bit. Next, what fan are you using on your cooler? try shoving a noctua 92mm if you can instead of the current cpu cooler fan, they run quiet as fuck. Next, half your fucking issue is that you have it horizontal. the case performs vastly better in the vertical position and your gpu temps and thus noise levels would be vastly lower.