Sorry i am a bit late to this thread. I have a HAF 922. I can see you mounting it to the top of the chassis but the XM case has that fan shroud thingy on top of the case covering the one 200mm fan that came with your case making the inside top of the case closer to the MB then my 922.
Also your case has a 140mm rear fan opening that can also hold 120mm fans that I think would have been ideal since the rear fan mount is slightly oversized for 120mm fans and it has that nice coolermaster honeycomb design so it hardly interferes with air flow.
I mounted my 120mm radiator AIO on the rear of my 922 case. I wanted a push pull setup but my cooler only came with 4 long machined bolts. The a lightbulb went off in my head. I only used 2 long machined screws on each side of the push pull setup along with 2 of the short fat standard fan screws that we all have lying around. so i mounted the one fan "my pull fan" to the rear fan mount of my case using the 2 fat fan screws that screw into the plastic fan frame one each on opposing corners. Then I pushed two of the long machined screws through the remaining opposing corners to mount the 120mm radiator. Then i used my remaining 2 machined screws to mount my push fan to the radiator. It turned out to be a nice and sturdy mount even thoungh i only used 2 of the long machined screws on each side.
It beat having to run to the store and it also has its bonuses. It dissembles much faster when i have to clean the radiator and fans.
As for the fans i am using I picked up 4 of the black Cougar Vortex fans at $17 each. I put the build quality right up there with Noctua but they look a helluva lot better plus they are super quiet also. They also have special curved fins sticking out a wee bit from the fan frames that directs the air strait out of the fan instead of cone shaped airflow exiting the fan. A good design for pushing air through a radiator in my opinion.
I am not knocking Noctua fans at all they are awesome! just very very ugly, but rusty brown and tan are there trademark. I have No led's or disco balls inside my case just the red LED's on the front 200mm fan that came with my HAF 922...luckily it has a switch to shut the red LED's off
I am curious to what cooler you where using and your temps with the old cooler and your new AIO h60. Also if you run that $1000 990 6 core monster overclocked. If so does the H60 give you better temps that you can run a better 24/7 overclock?