I'm not sure there's really a need to put an aftermarket cooler on this card, thus far it has been the most silent & lowest temps of any card I have ever owned.
As far as the fitment that's a hard one to say for your nCase, it fits in my IN-WIN 901 with 2-3 mm to spare... I actually had to find a modded low profile 8-pin cable to allow my glass side panel to be installed.
What I can tell you is the card comes out about 26mm from the pci slot where you screw in the graphics card, a non-sleeved/bare wire 8-pin will protrude around 8mm past that.
ebay user new_used_computer_parts has a selection of low profile PCI-E extensions you can buy, he will also custom make them to your specifications as he did with mine.