Wow...Just an update.
Since I got my Dark Knight, I changed the fan to where it was blowing out with the 200mm fan. With a 1.54 vcore(OCCT), getting temps of 56c(MAX!!) at 3.8GHz(During OCCT.) I'm very impressed with this heatsink...this is stock(as in right out of the box) btw with some MX-2. Idles around 38c too. Not sure how stable it is, but it just got done doing a 24 minute High Priority OCCT test. I'm going to test it more later of course.
So I wouldn't consider it rock solid stable.