I had a R4 which I had a D14 air cooler in. the case was great, the cooler was great, all was well.
I then moved to a Define S which I installed a custom water system in, with a 30mm 280 in front and a 30mm 280 at top. Technically, the case doesn't support that at top, and it was DAMN close clearing the ram for sure. Also, I couldn't use the proper fan screw mounts for the radiators because they just dont fit there
Point is, I'm sure you could fit the rad there if your willing to drill a hole or two. 50% chance you could bodge the rad up there without drilling holes (like I did with the define s, though I only used 5 of 8 screws), maybe the fans will have to be external though, but dont bother if you want an easy install, just install equipment that fits in your case.
Just because you can get 2x 140mm fans up there, doesn't mean they are spaced out to accommodate a 280 radiator, and it defiantly doesn't mean there is room for an internal radiator AND internal fan in that space.