I'm currently running a 360 external rad in an Antec case with an EKWB CPU WB. I have no reservoir, as the rad has a top fillport. The system always sounds like it has air bubbles, but I suspect it's the WB making the noise. The CPU (i6700k) runs a bit warm when doing video encoding. So I'm moving to a Coolstream 420 with Vardar fans, an Enthoo Primo case and a Photon 270 reservoir. My preference is to mount the rad in the bottom of the Phantek case below the reservoir. The one concern I have is the four legged creature that lives near my case. I know that the Phantek has slide out air filters on the bottom of the case, I'm just not sure how effective these are? I know it's not supposed to matter if the rad is the low point in the loop, but I'd prefer to avoid the case flipping I remember from the past. I'd also like to avoid adding a fillport above the rad, if I mount the rad in the top of the case. Any thoughts? I'll likely be moving to an i8700K or a Ryzen 1800x in the future, so the WC change is phase one of the upgrade.