Hey,
So what did you get in the end?
I'm also looking for a new 280mm rad, I have cooler master haf 932 adv, but I ordered 120to 140mm fan mounts (bitspower @caseking) , the case has holes for 240mm but space for 280mm on top .. so far I narrowed it down to these
1) corsair h115i pro (best noise/perf)
2) cryorig A80 (great and cools vrm, a bit noisy - I use aisuite for fan control atm for h90 in p/p)
3) kraken x62 (seems good)
4) ?
5) asus ryujin 240 / fractal celsius s24
Was about to order ekwb mlc 240 Phoenix - winter sale whole set just 150e, but then I saw tubing issues with them quick connects and filling liquid - air noise bubbles.